Nodeless superconductivity in 4H$_{b}$-TaS$_{2}$ with broken time reversal symmetry

Fanyu Meng; Hechang Lei; Huiqiu Yuan; Jiawen Zhang; Jin Zhan; Michael Smidman; Yanen Huang; Ye Chen; Yu Liu; Yuwei Zhou

REVIEW 3 major objections 5 minor 48 references

Nodeless superconductivity in 4H$_{b}$-TaS$_{2}$ with broken time reversal symmetry

T0 review · 3 major / 5 minor · reviewed 2026-08-06 · deepseek-v4-flash

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Pith's one-line read Penetration depth and specific heat show nodeless, two-gap superconductivity in 4Hb-TaS2.

desk verdict New TDO penetration depth data on Se-doped 4Hb-TaS2 support nodeless two-gap superconductivity, but the title overstates the material and the thermal conductivity conflict remains unresolved. read the letter →

arxiv 2507.07584 v1 pith:B7XNXX7O submitted 2025-07-10 cond-mat.supr-con

Yuwei Zhou , Fanyu Meng , Yanen Huang , Jiawen Zhang , Jin Zhan , Ye Chen , Yu Liu , Hechang Lei

show 2 more authors

Michael Smidman Huiqiu Yuan

This is my paper

classification cond-mat.supr-con

keywords 4Hb-TaS2superconductinggapstructurenodelesssuperconductivitytwo-gaps-wavemodelmagneticpenetrationdepthtime-reversalsymmetrybreakingspecificheattransitionmetaldichalcogenides

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper sets out to determine whether the superconducting order parameter in the layered van der Waals compound 4Hb-TaS2 has nodes. Using penetration-depth and specific-heat measurements on crystals with 1% of the sulfur replaced by selenium, it finds exponentially activated behavior in both quantities at low temperature — the signature of a fully gapped superconductor — and shows the superfluid density is described by a two-gap s-wave model. If correct, the result rules out pairing states with symmetry-enforced nodes ($B_{1u}$ and $E_{2g}$) and, combined with previously reported time-reversal symmetry breaking, favors a chiral $p+ip$-like order parameter. This matters because 4Hb-TaS2 is a candidate for topological superconductivity, and the gap structure determines whether such a state can exist.

What carries the argument

The argument is carried by the temperature dependence of the magnetic penetration depth, measured with a tunnel-diode oscillator and converted to superfluid density via $\rho_s(T)=[\lambda(0)/\lambda(T)]^2$ with $\lambda(0)=487$ nm taken from muon-spin-rotation results. In a clean, fully gapped superconductor, $\Delta\lambda(T)$ decays as $\sqrt{\pi\Delta(0)/2k_BT}\,\exp[-\Delta(0)/k_BT]$ at $T \ll T_c$, whereas nodal states give power laws (approximately $T$ for line nodes and $T^2$ for point nodes in the clean limit). The two-gap s-wave model enters as a weighted sum of two single-gap superfluid densities, $\rho_s(T)=x\rho_{s1}(\Delta_1)+(1-x)\rho_{s2}(\Delta_2)$, and the same gaps are inserted into the BCS entropy expression to model $C_e(T)/T$; the consistency of these two independent fits is what supports nodeless multigap pairing.

What would settle it

Measuring $\Delta\lambda(T)$ or $C_e(T)$ on undoped 4Hb-TaS2, or on the same Se-doped crystals below 0.1 K, and finding a power-law $\Delta\lambda(T)\propto T$ or $T^2$ instead of an exponential, or a specific-heat linear term that survives as $T\to0$, would falsify the nodeless fully gapped claim.

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Extended reading notes

Core claim

The central claim is that the superconducting gap of 4Hb-TaS2 is nodeless and multigap. On the Se-substituted crystals, the penetration-depth shift $\Delta\lambda(T)$ flattens below $T_c/3$ and follows the exponential form $\Delta\lambda(T)\propto \exp[-\Delta(0)/k_BT]$ with $\Delta(0)=0.99(2)k_BT_c$, and the electronic specific heat shows the same activated dependence. The superfluid density $\rho_s(T)=[\lambda(0)/\lambda(T)]^2$, normalized with $\lambda(0)=487$ nm from muon-spin-rotation measurements, is well fitted by a two-gap s-wave model and clearly deviates from $p$-wave and $d$-wave forms with point and line nodes. The same gap parameters, $\Delta_1(0)=0.89(2)k_BT_c$ and $\Delta_2(0)=1.96(1)k_BT_c$ with about 10% weight on the smaller gap, also describe the specific heat, and the paper concludes that the $B_{1u}$ and $E_{2g}$ nodal order parameters are excluded, leaving a nodeless multigap state that is likely chiral odd-parity $p+ip$ if the time-reversal symmetry breaking is intrinsic.

Load-bearing premise

The paper assumes that substituting 1% of the sulfur with selenium to stabilize the crystals does not change the superconducting gap structure of pure 4Hb-TaS2, even though a prior thermal-conductivity study of the undoped compound reported gapless behavior.

Editorial extensions

If this is right

Below $T_c/3$, both $\Delta\lambda(T)$ and $C_e(T)$ grow with temperature exponentially rather than as a power law, so the measured directions exclude line and point nodes in the superconducting gap.
The superfluid density and specific heat are jointly reproduced by a two-gap s-wave model with $\Delta_1(0)=0.89(2)k_BT_c$, $\Delta_2(0)=1.96(1)k_BT_c$, and about 10% weight on the smaller gap.
The symmetry-enforced nodal order parameters $B_{1u}$ and $E_{2g}$ are ruled out, narrowing the possible pairing symmetries to the even-parity $A_{1g}$ state or odd-parity states such as $E_{1u}$.
If the time-reversal symmetry breaking detected by muon-spin rotation is intrinsic to the superconducting state, a complex $p+ip$ pairing is favored over a conventional $A_{1g}$ state, although phase-sensitive experiments are still needed.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

The measurements were made on 4Hb-TaS$_{1.99}$Se$_{0.01}$, not the pure compound named in the title; the conclusion transfers to pure 4Hb-TaS2 only if the 1% selenium substitution leaves the gap structure unchanged, which a future undoped-crystal measurement could test.
With the small fitted gap $\Delta_1(0)\approx 0.89 k_BT_c$, the exponential tail at the very lowest temperatures should have a measurable slope; a high-resolution measurement below 0.1 K could reveal any residual power-law component from gap anisotropy or accidental nodes.
The residual specific-heat intercept $\gamma_{\rm res}=0.3$ mJ mol$^{-1}$ K$^{-2}$, attributed to nonsuperconducting stacking faults, leaves room for a small gapless fraction; cleaner crystals should lower this intercept and sharpen the exponential signatures.
If nodeless gaps and time-reversal symmetry breaking coexist in the same compound, 4Hb-TaS2 becomes a rare case where chiral pairing does not force nodal quasiparticles; Josephson-interferometry or polar-Kerr experiments could check that combination directly.

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

Colleague,

Read the Zhou et al. paper on 4Hb-TaS2. The useful new thing is the first tunnel-diode-oscillator penetration depth study on this system (1% Se-doped crystals), and it shows a clear exponential flattening in Δλ(T) below Tc/3, consistent across two samples and two field orientations. The superfluid density deviates strongly from p- and d-wave fits, and a two-gap s-wave model with a small gap Δ1(0)=0.89 kBTc (10% weight) and a large gap 1.96 kBTc describes the data well. They then fix those parameters and fit the specific heat, which works—that is a legitimate consistency check, even if it is not independent prediction. The µSR-derived superfluid density from Ref. 28 also lines up. That is solid experimental work and the nodeless conclusion is the most natural reading of the data.

The soft spots are real but not fatal. First, the title says 4Hb-TaS2 but all measurements are on 4Hb-TaS1.99Se0.01. The 1% Se substitution is motivated by sample quality, and it probably does not change pairing, but the paper never explicitly justifies the extrapolation. That matters because a thermal conductivity study (Ref. 32) reported gapless behavior on pure 4Hb-TaS2; the paper cites it in the introduction but never returns to explain the conflict. That is the biggest gap.

Second, the exponential fit rests on Eq. 1 over a narrow range (T < Tc/3), and the extracted Δ(0)=0.99 kBTc is below the BCS value. The authors interpret this as multigap evidence, which is plausible, but a single exponential over that range cannot cleanly distinguish a small isotropic gap from a distribution of small gaps or from strong-coupling corrections. The power-law exponent analysis in the inset is not discriminating; n just rises continuously as T_up is reduced, which is also what an activated form does. The clean-limit estimate (ℓ=74.5 nm vs ξBCS=23.3 nm) is reasonable but derived from a Drude estimate, so the dirty-limit mimicry argument is at least a caveat.

Third, the residual γ_res of 0.3 mJ/mol K² is attributed to a nonsuperconducting fraction, consistent with prior work, but it is a reminder that the sample is not perfectly single phase. None of these are load-bearing flaws; together they make the conclusion "nodeless in the measured doped crystals" solid, and "nodeless in pure 4Hb-TaS2" conditional.

This paper is for the superconducting-gap spectroscopy community and TMD specialists. It deserves a serious referee. I would recommend sending it to review, with the expectation that the authors address the Se-doping extrapolation and the thermal conductivity discrepancy directly in revision.

Referee Report

3 major / 5 minor

Summary. This paper reports tunnel-diode-oscillator magnetic penetration-depth measurements down to 0.33 K and specific-heat measurements down to 0.4 K on single crystals of 4Hb-TaS1.99Se0.01. The authors find that Δλ(T) flattens at low temperature and is fitted by an activated exponential form for T < Tc/3 with a fitted gap Δ(0) ≈ 0.99 kBTc, below the weak-coupling BCS value; a power-law analysis yields an exponent that grows as the fitting window shrinks. The normalized superfluid density is well described over the full temperature range by a two-gap s-wave model with Δ1(0) = 0.89 kBTc at about 10% weight and Δ2(0) = 1.96 kBTc, while p-wave and d-wave models fail. Fixing these two-gap parameters, the electronic specific heat, including a Schottky term and a residual γres = 0.3 mJ/mol K², is claimed to be consistently described. The authors conclude that 4Hb-TaS2, as represented by the Se-substituted crystals, has a nodeless multigap superconducting order parameter, which rules out the symmetry-enforced nodal B1u and E2g representations and leaves nodeless channels consistent with the previously reported time-reversal symmetry breaking.

Significance. If the conclusion holds, the paper meaningfully constrains the pairing symmetry of a candidate topological and time-reversal-symmetry-breaking superconductor, narrowing the symmetry classification to nodeless channels and thereby sharpening the theoretical discussion of 4Hb-TaS2. The study's concrete strengths are the reproducible three-sample TDO data in two field orientations, the explicit comparison of the measured superfluid density with p-wave and d-wave models, the cross-observable consistency check in which two-gap parameters fitted to one quantity are reused for a second, the public data-availability DOI (Ref. 48), and the transparent statement of the residual normal fraction. The central nodeless claim, however, rests on assumptions that are asserted rather than demonstrated: the clean-limit electrodynamics underlying the exponential analysis, and the transferability of conclusions from the 1% Se-substituted crystals to the nominally undoped compound named in the title. These concerns are fixable within the manuscript's scope, but they are load-bearing for the paper's headline claim.

major comments (3)

[Section II; title and abstract] The title and abstract attribute the conclusions to 4Hb-TaS2, but all measurements were made on 4Hb-TaS1.99Se0.01, and Section II states that the 1% Se substitution was introduced to stabilize the structure and increase the superconducting volume fraction. Since the cited thermal-conductivity study of (presumably undoped) 4Hb-TaS2 (Ref. 32) reports gapless behavior, the implicit assumption that 1% Se does not alter the gap structure is load-bearing for the generalization of the central claim. The authors should either scope the title and abstract to the Se-substituted compound or justify transferability explicitly: state the composition of the samples used in the comparative studies (Refs. 28 and 32), quantify the superconducting volume fraction of the present crystals, and discuss directly whether the residual linear term of Ref. 32 can be reconciled with the present nodeless picture, for instance as a normal-state fraction rather than nodal quasiparticles.
[Section III, Fig. 2(b), Eq. (1)] The exponential analysis that anchors the nodeless claim uses Eq. (1), which is derived for a clean-limit, single-gap, isotropic s-wave superconductor. The clean-limit classification rests on an estimated mean free path ℓ = 74.5 nm obtained from ρ0 = 69.3 μΩ cm, but the inputs of that estimate (e.g., carrier density or Hall constant) are not given, and ℓ/ξBCS ≈ 3.2 is only modestly in the clean limit for a layered multiband compound. In the dirty or intermediate regime, a nodal or near-nodal state can produce T^2-like low-temperature Δλ(T), and the reported power-law exponents n ≈ 3–4 over the window 0.33–1 K do not by themselves exclude that possibility. The skeptical objection that a single exponential fit over a narrow range cannot uniquely exclude an impurity-broadened small-gap state is therefore valid as far as that fit alone is concerned; the paper's case is stronger than that, since it also shows an exponent that rises as the fitting window shrinks and a two-gap s-wave fit that works over the full temperature range. To make the robustness point conclusive, the authors should state the inputs to the ℓ estimate, show an Arrhenius plot with residuals over the full fitted range, and comment on the dirty-limit alternative using the estimated scattering rate.
[Section III, Fig. 4, Eq. (4)] The abstract's statement that both the specific heat and Δλ(T) display an exponentially activated temperature dependence overstates the specific-heat channel: the low-temperature Ce(T) data show an upturn attributed to a Schottky term plus a finite residual γres = 0.3 mJ/mol K², and the activated behavior is only recovered inside the model of Eq. (4), whose three additional parameters (ΔE, n, γres) are freely fitted and reported without uncertainties or goodness-of-fit statistics. In addition, reusing the weight x = 0.099 from the superfluid-density fit in the specific-heat calculation assumes that the superfluid-weight fraction equals the Sommerfeld-weight fraction of the small-gap band; this equality is not generally valid in two-band superconductors and should either be justified or tested by freeing x in the specific-heat fit. Finally, since γres is attributed to a nonsuperconducting fraction, the paper should quantify that fraction (e.g., from the ZFC shielding signal in Fig. 1(b)) and discuss its effect on the normalization ρs = [λ(0)/λ(T)]^2 with λ(0) = 487 nm taken from μSR.

minor comments (5)

[Inset of Fig. 2(b)] The exponent analysis is shown only for sample #2 and without uncertainties; showing the same analysis for sample #1 and adding error bars would make the claim that n rises as T_up decreases quantitative.
[Section III, mean free path estimate] The estimate ℓ = 74.5 nm refers to Ref. 41 but does not state the carrier density or effective mass used; one sentence with these inputs would make the clean-limit claim checkable.
[Abstract and affiliations] The abstract's 'two-gaps-wave model' should read 'two-gap s-wave model', and affiliation 3 contains the typo 'Educatoin'.
[Section III, Schottky parameters] The Schottky level splitting ΔE = 4.6 × 10^-24 J is more transparent expressed as approximately 0.33 K or in μeV.
[Section III, μSR comparison] When the consistency of the μSR-derived ρs(T) with the TDO data is invoked, please specify the temperature range and the criterion for 'consistent', since this cross-check supports the λ(0) = 487 nm normalization used throughout.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the penetration-depth, superfluid-density, and specific-heat analyses are independent empirical fits, not derivations that reduce to their own inputs.

full rationale

The paper's central claim is that 4Hb-TaS1.99Se0.01 is a fully gapped multigap superconductor, supported by three experimental inputs: an exponentially activated low-temperature penetration-depth shift, a superfluid density fit with a two-gap s-wave model, and a specific-heat fit using the same two-gap parameters. None of these steps is circular. The low-temperature Δλ(T) is fit with the standard BCS activated expression (Eq. 1), and the extracted Δ(0) = 0.99 kBTc is then interpreted as smaller than weak-coupling BCS; this interpretation is model-dependent but not self-referential. The superfluid density is independently calculated from Δλ(T) with λ(0) taken from prior muon-spin-rotation work (Ref. [28]) and is compared against s-, p-, and d-wave models; the two-gap s-wave model is selected because it fits the data, while the nodal models do not. The specific-heat analysis fixes the two-gap parameters from the superfluid-density fit and then checks that the same parameters describe a different measured quantity (Ce/T). This is a consistency check across data sets, not a fitted parameter renamed as a prediction. The irreps discussion cites external symmetry analyses (Refs. [30,31]) rather than a self-citation chain, and the conflicting thermal-conductivity result (Ref. [32]) is presented as an open issue rather than used as load-bearing support. The use of Se-doped crystals is a sample-composition caveat, not circularity. Overall, the derivation chain is conventional phenomenology: measurements are fitted with standard models, and the conclusions follow from the quality of those fits rather than from an identity between input and output.

Assumptions & free parameters 4 free parameters · 5 assumptions · 0 invented entities

The central claim of nodeless superconductivity depends primarily on the exponential temperature dependence, which is model-independent. The quantitative two-gap parameters are fitted to the same data, and the specific heat analysis reuses those parameters, so the model parameters are not independently derived. The key assumptions are the clean-limit condition, the representativeness of the doped crystals, and the Schottky interpretation of the specific heat upturn.

free parameters (4)

Single-gap s-wave Δ(0) from Δλ fit = 0.99(2) k_B T_c
Fitted to the low-temperature exponential tail of Δλ below T_c/3 using Eq. 1.
Two-gap parameters Δ1(0), Δ2(0), x = Δ1=0.89(2) k_B T_c, Δ2=1.96(1) k_B T_c, x=0.099(6)
Fitted to the superfluid density using a two-gap s-wave model; determine the temperature dependence of the superfluid density and subsequently fixed in the specific heat analysis.
Schottky parameters ΔE and n = ΔE=4.6e-24 J, n=0.00058
Fitted to the low-temperature specific heat upturn together with γ_res.
Residual Sommerfeld coefficient γ_res = 0.3 mJ mol^-1 K^-2
Fitted in the specific heat analysis; attributed to a nonsuperconducting fraction.

assumptions (5)

standard math BCS formulas for entropy and superfluid density (Eqs. 2-5) are valid for an s-wave multiband superconductor.
Used to compute superfluid density and specific heat from assumed gap functions.
domain assumption The sample is in the clean limit, as estimated from λ(0), ρ0, and coherence length.
Justifies using clean-limit formulas for penetration depth and superfluid density; Section III, text after Fig. 1.
domain assumption 1% Se doping does not alter the superconducting gap structure of 4Hb-TaS2.
The measurements are on doped crystals while the conclusions are stated for the pure compound; Section II, first sentence.
domain assumption The low-temperature specific heat upturn is a Schottky anomaly from paramagnetic impurities, not an intrinsic electronic contribution.
Needed to extract the intrinsic electronic specific heat; Section III, around Eq. 4.
standard math The calibration factor G converts TDO frequency shift to penetration depth using standard demagnetization formulas.
Required for obtaining Δλ from Δf; Section II, TDO description.

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Cite this review

Pith. "Pith review of Nodeless superconductivity in 4H$_{b}$-TaS$_{2}$ with broken time reversal symmetry." pith.science (2026). https://pith.science/paper/B7XNXX7O

@misc{pith2026250707584,
  author       = {Pith},
  title        = {Pith review of: Nodeless superconductivity in 4H$_b$-TaS$_2$ with broken time reversal symmetry},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/B7XNXX7O}},
  note         = {Machine review of arXiv:2507.07584}
}

abstract

The transition metal dichalcogenide 4H$_{b}$-TaS$_{2}$ exhibits characteristics of topological edge modes and two-component superconductivity with time-reversal symmetry breaking (TRSB). The nature of the superconducting order parameter is a crucial issue that requires experimental investigation. Here, we report measurements of the magnetic penetration depth using a tunnel-diode-oscillator based technique, as well as the specific heat. Both the specific heat and the change in magnetic penetration depth ($\Delta$$\lambda$(T)) display an exponentially-activated temperature dependence, providing evidence for nodeless superconductivity in 4H$_{b}$-TaS$_{2}$. Moreover, the deduced superfluid density can be well described by a two-gap $s$-wave model, and such multigap superconductivity is consistent with there being multiple bands crossing the Fermi energy. These results constrain the possible pairing symmetries of 4H$_{b}$-TaS$_{2}$.

Figures

Figures reproduced from arXiv: 2507.07584 by the authors.

**Figure 2.** FIG. 2. (Color online) (a) Temperature dependence of the [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗

**Figure 3.** FIG. 3. (Color online) Temperature dependence of the nor [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗

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Works this paper leans on

48 extracted references · 45 canonical work pages

[1]

Sigrist and K

M. Sigrist and K. Ueda, Phenomenological theory of unconventional superconductivity, Reviews of Modern physics63, 239 (1991)

work page 1991
[2]

S. K. Ghosh, M. Smidman, T. Shang, J. F. Annett, A. D. Hillier, J. Quintanilla, and H. Yuan, Recent progress on superconductors with time-reversal symmetry breaking, Journal of Physics: Condensed Matter33, 033001 (2020)

2020
[3]

G. Luke, A. Keren, L. Le, W. Wu, Y. Uemura, D. Bonn, L. Taillefer, and J. Garrett, Muon spin relaxation in UPt3, Physical review letters71, 1466 (1993)

work page 1993
[4]

G. M. Luke, Y. Fudamoto, K. Kojima, M. Larkin, J. Mer- rin, B. Nachumi, Y. Uemura, Y. Maeno, Z. Mao, Y. Mori, et al., Time-reversal symmetry-breaking superconductiv- ity in Sr 2RuO4, Nature394, 558 (1998)

work page 1998
[5]

J. Xia, Y. Maeno, P. T. Beyersdorf, M. Fejer, and A. Ka- pitulnik, High resolution polar kerr effect measurements of Sr 2RuO4: Evidence for broken time-reversal symme- try in the superconducting state, Physical review letters 97, 167002 (2006)

work page 2006
[6]

Heffner, J

R. Heffner, J. Smith, J. Willis, P. Birrer, C. Baines, F. Gygax, B. Hitti, E. Lippelt, H. Ott, A. Schenck, et al., New phase diagram for (U,Th)Be13: A muon-spin- resonance andH c1 study, Physical review letters65, 2816 (1990)

work page 1990
[7]

Schemm, R

E. Schemm, R. Baumbach, P. Tobash, F. Ronning, E. Bauer, and A. Kapitulnik, Evidence for broken time- reversal symmetry in the superconducting phase of URu2Si2, Physical Review B91, 140506 (2015)

work page 2015
[8]

Schemm, W

E. Schemm, W. Gannon, C. Wishne, W. Halperin, and A. Kapitulnik, Observation of broken time-reversal sym- metry in the heavy-fermion superconductor UPt 3, Sci- ence345, 190 (2014)

work page 2014

Show all 48 references

[9]

A. D. Hillier, J. Quintanilla, and R. Cywinski, Evi- dence for time-reversal symmetry breaking in the noncen- 6 trosymmetric superconductor LaNiC 2, Physical review letters102, 117007 (2009)

2009
[10]

A. D. Hillier, J. Quintanilla, B. Mazidian, J. F. Annett, and R. Cywinski, Nonunitary triplet pairing in the cen- trosymmetric superconductor LaNiGa2, Physical Review Letters109, 097001 (2012)

2012
[11]

Z. Weng, J. Zhang, M. Smidman, T. Shang, J. Quin- tanilla, J. F. Annett, M. Nicklas, G. Pang, L. Jiao, W. Jiang,et al., Two-gap superconductivity in LaNiGa 2 with nonunitary triplet pairing and even parity gap sym- metry, Physical Review Letters117, 027001 (2016)

2016
[12]

Bhattacharyya, D

A. Bhattacharyya, D. Adroja, J. Quintanilla, A. Hillier, N. Kase, A. Strydom, and J. Akimitsu, Broken time- reversal symmetry probed by muon spin relaxation in the caged type superconductor Lu5Rh6Sn18, Physical Review B91, 060503 (2015)

2015
[13]

A. Wang, Z. Nie, F. Du, G. Pang, N. Kase, J. Akimitsu, Y. Chen, M. Gutmann, D. Adroja, R. Perry,et al., Node- less superconductivity in Lu 5−xRh6Sn18+x with broken time reversal symmetry, Physical Review B103, 024503 (2021)

2021
[14]

W. Xie, P. Zhang, B. Shen, W. Jiang, G. Pang, T. Shang, C. Cao, M. Smidman, and H. Yuan, CaPtAs: A new non- centrosymmetric superconductor, Science China Physics, Mechanics & Astronomy63, 237412 (2020)

2020
[15]

Shang, M

T. Shang, M. Smidman, A. Wang, L.-J. Chang, C. Baines, M.-K. Lee, Z. Nie, G. Pang, W. Xie, W. Jiang, et al., Simultaneous nodal superconductivity and time- reversal symmetry breaking in the noncentrosymmet- ric superconductor CaPtAs, Physical review letters124, 207001 (2020)

2020
[16]

Singh, J

D. Singh, J. Barker, A. Thamizhavel, D. M. Paul, A. Hillier, and R. Singh, Time-reversal symmetry break- ing in the noncentrosymmetric superconductor Re 6Hf: Further evidence for unconventional behavior in theα- Mn family of materials, Physical Review B96, 180501 (2017)

2017
[17]

G. Pang, Z. Nie, A. Wang, D. Singh, W. Xie, W. Jiang, Y. Chen, R. Singh, M. Smidman, and H. Yuan, Fully gapped superconductivity in single crystals of noncen- trosymmetric Re 6Zr with broken time-reversal symme- try, Physical Review B97, 224506 (2018)

2018
[18]

Singh, S

D. Singh, S. KP, J. Barker, D. M. Paul, A. Hillier, and R. Singh, Time-reversal symmetry breaking in the non- centrosymmetric superconductor Re6Ti, Physical Review B97, 100505 (2018)

2018
[19]

J. A. Wilson, F. Di Salvo, and S. Mahajan, Charge- density waves and superlattices in the metallic layered transition metal dichalcogenides, Advances in Physics 24, 117 (1975)

1975
[20]

Wilson, F

J. Wilson, F. Di Salvo, and S. Mahajan, Charge-density waves in metallic, layered, transition-metal dichalco- genides, Physical review letters32, 882 (1974)

1974
[21]

Manzeli, D

S. Manzeli, D. Ovchinnikov, D. Pasquier, O. V. Yazyev, and A. Kis, 2D transition metal dichalcogenides, Nature Reviews Materials2, 1 (2017)

2017
[22]

Y. Liu, L. Li, W. Lu, R. Ang, X. Liu, and Y. Sun, Co- existence of superconductivity and commensurate charge density wave in 4Hb-TaS 2−xSex single crystals, Journal of Applied Physics115(2014)

2014
[23]

Di Salvo, B

F. Di Salvo, B. Bagley, J. Voorhoeve, and J. Waszczak, Preparation and properties of a new polytype of tantalum disulfide (4Hb-TaS2), Journal of Physics and Chemistry of Solids34, 1357 (1973)

1973
[24]

Y. Fei, Z. Wu, W. Zhang, and Y. Yin, Understanding the mott insulating state in 1T-TaS 2 and 1T-TaSe 2, AAPPS Bulletin32, 20 (2022)

2022
[25]

K. T. Law and P. A. Lee, 1T-TaS 2 as a quantum spin liquid, Proceedings of the National Academy of Sciences 114, 6996 (2017)

2017
[26]

H. Lin, W. Huang, K. Zhao, S. Qiao, Z. Liu, J. Wu, X. Chen, and S.-H. Ji, Scanning tunneling spectroscopic study of monolayer 1T-TaS 2 and 1T-TaSe 2, Nano Re- search13, 133 (2020)

2020
[27]

Sipos, A

B. Sipos, A. F. Kusmartseva, A. Akrap, H. Berger, L. Forr´ o, and E. Tutiˇ s, From mott state to supercon- ductivity in 1T-TaS 2, Nature Materials7, 960 (2008)

2008
[28]

Ribak, R

A. Ribak, R. M. Skiff, M. Mograbi, P. Rout, M. Fischer, J. Ruhman, K. Chashka, Y. Dagan, and A. Kanigel, Chi- ral superconductivity in the alternate stacking compound 4Hb-TaS2, Science advances6, eaax9480 (2020)

2020
[29]

A. K. Nayak, A. Steinbok, Y. Roet, J. Koo, G. Mar- galit, I. Feldman, A. Almoalem, A. Kanigel, G. A. Fiete, B. Yan,et al., Evidence of topological boundary modes with topological nodal-point superconductivity, Nature physics17, 1413 (2021)

2021
[30]

Almoalem, I

A. Almoalem, I. Feldman, I. Mangel, M. Shlafman, Y. E. Yaish, M. H. Fischer, M. Moshe, J. Ruhman, and A. Kanigel, The observation ofπ-shifts in the little-parks effect in 4Hb-TaS 2, Nature Communications15, 4623 (2024)

2024
[31]

M. H. Fischer and J. Goryo, Symmetry and gap classifica- tion of non-symmorphic SrPtAs, Journal of the Physical Society of Japan84, 054705 (2015)

2015
[32]

H. Wang, Y. Jiao, F. Meng, X. Zhang, D. Dai, C. Tu, C. Zhao, L. Xin, S. Huang, H. Lei,et al., Evidence for multiband gapless superconductivity in the topolog- ical superconductor candidate 4Hb-TaS 2, arXiv preprint arXiv:2412.08450 (2024)

2024 arXiv
[33]

F. Meng, Y. Fu, S. Pan, S. Tian, S. Yan, Z. Li, S. Wang, J. Zhang, and H. Lei, Extreme orbital ab-plane upper critical fields far beyond the pauli limit in 4Hb-Ta(S,Se)2 bulk crystals, Physical Review B109, 134510 (2024)

2024
[34]

Persky, A

E. Persky, A. V. Bjørlig, I. Feldman, A. Almoalem, E. Altman, E. Berg, I. Kimchi, J. Ruhman, A. Kanigel, and B. Kalisky, Magnetic memory and spontaneous vor- tices in a van der waals superconductor, Nature607, 692 (2022)

2022
[35]

Almoalem, R

A. Almoalem, R. Gofman, Y. Nitzav, I. Mangel, I. Feld- man, J. Koo, F. Mazzola, J. Fujii, I. Vobornik, J. S´ an- chez Barriga,et al., Charge transfer and spin-valley lock- ing in 4Hb-TaS2, npj Quantum Materials9, 36 (2024)

2024
[36]

C. T. Van Degrift, Tunnel diode oscillator for 0.001 ppm measurements at low temperatures, Review of Scientific Instruments46, 599 (1975)

1975
[37]

Prozorov and R

R. Prozorov and R. W. Giannetta, Magnetic penetration depth in unconventional superconductors, Superconduc- tor Science and Technology19, R41 (2006)

2006
[38]

Prozorov, R

R. Prozorov, R. Giannetta, A. Carrington, and F. Araujo-Moreira, Meissner-london state in supercon- ductors of rectangular cross section in a perpendicular magnetic field, Physical Review B62, 115 (2000)

2000
[39]

Prozorov and V

R. Prozorov and V. G. Kogan, Effective demagnetizing factors of diamagnetic samples of various shapes, Physi- cal review applied10, 014030 (2018)

2018
[40]

Gross, B

F. Gross, B. Chandrasekhar, D. Einzel, K. Andres, P. Hirschfeld, H. Ott, J. Beuers, Z. Fisk, and J. Smith, Anomalous temperature dependence of the magnetic field 7 penetration depth in superconducting UBe 13, Zeitschrift f¨ ur Physik B Condensed Matter64, 175 (1986)

1986
[41]

Orlando, E

T. Orlando, E. McNiff Jr, S. Foner, and M. Beasley, Crit- ical fields, Pauli paramagnetic limiting, and material pa- rameters of Nb3Sn and V3Si, Physical Review B19, 4545 (1979)

1979
[42]

Fletcher, A

J. Fletcher, A. Carrington, P. Diener, P. Rodiere, J.-P. Brison, R. Prozorov, T. Olheiser, and R. Giannetta, Pen- etration depth study of superconducting gap structure of 2H-NbSe2, Physical review letters98, 057003 (2007)

2007
[43]

Carrington and F

A. Carrington and F. Manzano, Magnetic penetration depth of MgB 2, Physica C: Superconductivity385, 205 (2003)

2003
[44]

Y. Wang, T. Plackowski, and A. Junod, Specific heat in the superconducting and normal state (2-300 K, 0-16 T), and magnetic susceptibility of the 38 K superconductor MgB2: evidence for a multicomponent gap, Physica C: Superconductivity355, 179 (2001)

2001
[45]

Yang, J.-Y

H. Yang, J.-Y. Lin, H. Li, F. Hsu, C.-J. Liu, S.-C. Li, R.-C. Yu, and C.-Q. Jin, Order parameter of MgB 2: a fully gapped superconductor, Physical review letters87, 167003 (2001)

2001
[46]

Bouquet, Y

F. Bouquet, Y. Wang, R. Fisher, D. Hinks, J. Jorgensen, A. Junod, and N. Phillips, Phenomenological two-gap model for the specific heat of MgB 2, Europhysics Let- ters56, 856 (2001)

2001
[47]

Kumar Nayak, A

A. Kumar Nayak, A. Steinbok, Y. Roet, J. Koo, I. Feld- man, A. Almoalem, A. Kanigel, B. Yan, A. Rosch, N. Avraham,et al., First-order quantum phase transi- tion in the hybrid metal–mott insulator transition metal dichalcogenide 4Hb-TaS 2, Proceedings of the National Academy of...

2023
[48]

”Nodeless superconductivity in 4Hb-TaS 2 with broken time reversal symmetry” [Data set], 2025

Yuwei Zhou. ”Nodeless superconductivity in 4Hb-TaS 2 with broken time reversal symmetry” [Data set], 2025. doi:10.5281/zenodo.15688310

2025 doi

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.

[1] [1]

Sigrist and K

M. Sigrist and K. Ueda, Phenomenological theory of unconventional superconductivity, Reviews of Modern physics63, 239 (1991)

work page 1991

[2] [2]

S. K. Ghosh, M. Smidman, T. Shang, J. F. Annett, A. D. Hillier, J. Quintanilla, and H. Yuan, Recent progress on superconductors with time-reversal symmetry breaking, Journal of Physics: Condensed Matter33, 033001 (2020)

2020

[3] [3]

G. Luke, A. Keren, L. Le, W. Wu, Y. Uemura, D. Bonn, L. Taillefer, and J. Garrett, Muon spin relaxation in UPt3, Physical review letters71, 1466 (1993)

work page 1993

[4] [4]

G. M. Luke, Y. Fudamoto, K. Kojima, M. Larkin, J. Mer- rin, B. Nachumi, Y. Uemura, Y. Maeno, Z. Mao, Y. Mori, et al., Time-reversal symmetry-breaking superconductiv- ity in Sr 2RuO4, Nature394, 558 (1998)

work page 1998

[5] [5]

J. Xia, Y. Maeno, P. T. Beyersdorf, M. Fejer, and A. Ka- pitulnik, High resolution polar kerr effect measurements of Sr 2RuO4: Evidence for broken time-reversal symme- try in the superconducting state, Physical review letters 97, 167002 (2006)

work page 2006

[6] [6]

Heffner, J

R. Heffner, J. Smith, J. Willis, P. Birrer, C. Baines, F. Gygax, B. Hitti, E. Lippelt, H. Ott, A. Schenck, et al., New phase diagram for (U,Th)Be13: A muon-spin- resonance andH c1 study, Physical review letters65, 2816 (1990)

work page 1990

[7] [7]

Schemm, R

E. Schemm, R. Baumbach, P. Tobash, F. Ronning, E. Bauer, and A. Kapitulnik, Evidence for broken time- reversal symmetry in the superconducting phase of URu2Si2, Physical Review B91, 140506 (2015)

work page 2015

[8] [8]

Schemm, W

E. Schemm, W. Gannon, C. Wishne, W. Halperin, and A. Kapitulnik, Observation of broken time-reversal sym- metry in the heavy-fermion superconductor UPt 3, Sci- ence345, 190 (2014)

work page 2014