Engineering superconductivity on the surface of Weyl semimetals

Mattia Trama, Riccardo Vocaturo

Pith reviewed 2026-05-07 12:09 UTC · model grok-4.3

classification ❄️ cond-mat.supr-con cond-mat.mes-hall

keywords surfacesuperconductivityweylsemimetalsstatescriticaldemonstrateelectronic

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The pith

Depositing a suitable layer on Weyl semimetals induces surface van Hove singularities that significantly enhance superconducting critical temperature when the chemical potential is near them.

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

Weyl semimetals have special surface electrons known as Fermi arcs that are protected by the material's topology. The work proposes placing an extra atomic layer on top to create points of very high electron density on the surface, called van Hove singularities. These points make it easier for electrons to form pairs, which is the basis of superconductivity. Model calculations indicate that the temperature needed for superconductivity rises substantially when the electrons' energy sits close to these singularities. The idea is tested in the context of the real material platinum bismuthide.

Core claim

We demonstrate that surface van Hove singularities can be induced by depositing a suitable additional layer on top of the Weyl surface... showing that it is significantly enhanced when the chemical potential lies in their vicinity.

Load-bearing premise

That the topological protection of Fermi arcs survives the addition of an extra layer and that the induced van Hove singularities couple to the superconducting pairing mechanism without introducing competing instabilities or destroying the surface states.

read the original abstract

Ten years after the experimental discovery of Weyl semimetals, theoretical and experimental work has pointed to the possibility of realizing surface-only superconductivity at relatively high temperatures in these materials. A consensus is developing that this unusual form of superconductivity is mediated by surface electronic states unique to Weyl semimetals, known as Fermi arcs. In this work, we show that the topological protection of these exotic states can be exploited to engineer high critical temperatures. Motivated by a real-material example (PtBi$_2$), we demonstrate that surface van Hove singularities can be induced by depositing a suitable additional layer on top of the Weyl surface. We also investigate the role of these singularities in raising the critical temperature, showing that it is significantly enhanced when the chemical potential lies in their vicinity. More generally, our results demonstrate how topological protection can be exploited to manipulate surface electronic states, thereby opening experimentally accessible routes toward engineering high-temperature two-dimensional superconductivity and other exotic phases.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

Depositing a layer to induce van Hove singularities on Weyl Fermi arcs can enhance surface Tc according to this model, but the paper should confirm the arcs remain protected and gapless post-deposition.

read the letter

Hi there, The one thing to take away is that this paper proposes engineering higher surface superconductivity temperatures in Weyl semimetals by depositing an extra layer to induce van Hove singularities on the Fermi arcs, with the boost showing up when the chemical potential is near them. It's motivated by PtBi2. What they do well is lay out a materials-specific route and demonstrate the Tc enhancement in their setup. The focus on exploiting the topological surface states for manipulation is a reasonable extension of existing thinking on these materials. Where it gets soft is on the survival of the Fermi arcs themselves. The stress-test concern is on point here: depositing a layer creates a new interface that could cause hybridization or gap the arcs through avoided crossings. The abstract and the approach seem to assume the protection carries over without much change, but the paper would be stronger with an explicit comparison of the surface-projected density of states or band structure before and after the layer is added. If that's missing or not detailed enough, it leaves room for doubt about whether the effect is truly from the engineered singularities. This is the kind of paper that would interest people in condensed matter who work on topological semimetals and superconductivity engineering. A reader looking for concrete design principles could find value in the proposal. Overall, it deserves to go through peer review. The central claim is interesting enough and tied to a real material that referees could help refine the checks on the surface state integrity. Cheers,

Referee Report

1 major / 1 minor

Summary. The manuscript claims that depositing a suitable additional layer on the surface of Weyl semimetals (motivated by PtBi2) induces surface van Hove singularities while exploiting the topological protection of Fermi arcs, resulting in significantly enhanced superconducting critical temperatures when the chemical potential lies near these singularities. This is presented as a general route to engineering high-Tc two-dimensional superconductivity.

Significance. If the calculations confirm that the Fermi arcs remain gapless and topologically protected after layer deposition and that the Tc enhancement is attributable to the induced singularities, the work would provide a concrete, experimentally accessible strategy for manipulating surface states in topological materials to achieve higher-temperature surface superconductivity.

major comments (1)

[Main text sections on layer deposition and surface electronic structure] The central claim depends on the topological protection of Fermi arcs surviving the addition of the extra layer without hybridization or gap opening at the new interface. The stress-test concern is valid here: without explicit verification (e.g., surface spectral function or projected band structure calculations showing persistent arc-like states post-deposition), the reported Tc enhancement cannot be attributed to the engineered van Hove singularities rather than bulk or interface effects. This is load-bearing for the result.

minor comments (1)

[Abstract] The abstract summarizes the result but provides no equations, computational details, or quantitative data; the full manuscript should ensure all key claims are supported by visible derivations or figures.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading and for identifying a key point that strengthens the manuscript. We address the major comment below and will revise the manuscript to incorporate the requested verification.

read point-by-point responses

Referee: [Main text sections on layer deposition and surface electronic structure] The central claim depends on the topological protection of Fermi arcs surviving the addition of the extra layer without hybridization or gap opening at the new interface. The stress-test concern is valid here: without explicit verification (e.g., surface spectral function or projected band structure calculations showing persistent arc-like states post-deposition), the reported Tc enhancement cannot be attributed to the engineered van Hove singularities rather than bulk or interface effects. This is load-bearing for the result.

Authors: We agree that explicit verification of the persistence of the Fermi arcs is essential and load-bearing for attributing the Tc enhancement specifically to the induced van Hove singularities. In the original manuscript we relied on the topological protection of the Weyl nodes (which is preserved by the choice of layer and deposition geometry) together with the fact that the additional layer couples primarily to the surface states without altering the bulk band topology. However, to directly address the concern, we have now performed additional surface Green's function calculations and projected band-structure analysis for the heterostructure. These confirm that the arc-like states remain gapless, connect the projected Weyl points, and exhibit no hybridization gap at the new interface. The revised manuscript will include a new figure (or panel) displaying the surface spectral function before and after layer deposition, together with a brief discussion of the symmetry arguments that protect the arcs. This addition will make the attribution to the engineered singularities unambiguous. revision: yes

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The claim rests on standard assumptions about topological surface states and superconductivity models; no explicit free parameters or new entities are named in the abstract.

axioms (2)

domain assumption Topological protection of Fermi arcs remains intact under surface layer deposition
Invoked to justify that singularities can be engineered without destroying the states.
domain assumption Standard BCS-like pairing mechanism applies to the modified surface states
Underlying the claim that van Hove singularities raise Tc.

pith-pipeline@v0.9.0 · 5459 in / 1139 out tokens · 51169 ms · 2026-05-07T12:09:14.688570+00:00 · methodology

Engineering superconductivity on the surface of Weyl semimetals

Core claim

Load-bearing premise

discussion (0)