REVIEW 6 cited by
When Could Abelian Fractional Topological Insulators Exist in Twisted MoTe$_2$ (and Other Systems)
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
Signed reviews
abstract
Using comprehensive exact diagonalization calculations on $\theta \approx 3.7 ^{\circ}$ twisted bilayer MoTe$_2$ ($t$MoTe$_2$), as well as idealized Landau level models also relevant for lower $\theta$, we extract general principles for engineering fractional topological insulators (FTIs) in realistic situations. First, in a Landau level setup at $\nu=1/3+1/3$, we investigate what features of the interaction destroy an FTI. For both pseudopotential interactions and realistic screened Coulomb interactions, we find that sufficient suppression of the short-range repulsion is needed for stabilizing an FTI. We then study $\theta \approx 3.7 ^{\circ}$ $t$MoTe$_2$ with realistic band-mixing and anisotropic non-local dielectric screening. Our finite-size calculations only find an FTI phase at $\nu=-4/3$ in the presence of a significant additional short-range attraction $g$ that acts to counter the Coulomb repulsion at short distances. We discuss how further finite-size drifts, dielectric engineering, Landau level character, and band-mixing effects may reduce the required value of $g$ closer towards the experimentally relevant conditions of $t$MoTe$_2$. Projective calculations into the $n=1$ Landau level, which resembles the second valence band of $\theta\simeq 2.1^\circ$ $t$MoTe$_2$, do not yield FTIs for any $g$, suggesting that FTIs at low-angle $t$MoTe$_2$ for $\nu=-8/3$ and $-10/3$ may be unlikely. While our study highlights the challenges, at least for the fillings considered, to obtaining an FTI with transport plateaus, even in large-angle $t$MoTe$_2$ where fractional Chern insulators are experimentally established, we also provide potential sample-engineering routes to improve the stability of FTI phases.
Forward citations
Cited by 6 Pith papers
-
Generic integer and fractional quantum anomalous Hall crystals from interaction-driven band folding
Interaction-driven band folding on a triangular-lattice Chern band produces integer and fractional quantum anomalous Hall crystals whose Hall conductivity equals the filling of the folded mini-band, in both fermionic ...
-
Fractional Chern mosaic in supermoir\'e graphene
Helical trilayer graphene with momentum-dependent tunneling is predicted to host a fractional Chern mosaic at filling 3+1/3: local fractional Chern insulators whose fractionalization pattern varies on the supermoiré scale.
-
Universal Moir\'e-Model-Building Method without Fitting: Application to Twisted MoTe$_2$ and WSe$_2$
Continuum models for twisted MoTe2 and WSe2 are constructed directly from DFT by projecting the DFT Hamiltonian onto a basis of continuum-model terms, without nonlinear fitting.
-
Fractional Chern Insulators and Competing States in a Twisted MoTe$_2$ Lattice Model
Using infinite DMRG on cylinder geometries, the paper maps phase diagrams of twisted MoTe2 and shows that direct spin exchange stabilizes the Chern-ferromagnetic parent band while higher-band mixing favors charge dens...
-
Electromagnetic response and emergent topological orders in transition metal dichalcogenide MoTe$_2$ bilayers
In twisted MoTe2, a uniform Chern-Simons flux approximation predicts Jain-sequence fractional Chern insulators plus higher-Chern 'fractal' fractional Chern insulators, with electric fields able to close gaps and trigg...
-
Valley Order in Moir\'e Topological Insulators
At filling ν=1, intervalley-coherent states in opposite-Chern Landau level models are ground states only for reduced intravalley interactions, and their gapless spin mode rules them out as the sole explanation of the ...
Discussion (0). Continue with ORCID to comment.