Flat topological bands and eigenstate criticality in a quasiperiodic insulator
TLDR
In this paper, the authors analytically and numerically investigate the effects of downfolding a Brillouin zone and quench the kinetic energy by flattening bands, and discover a complex phase diagram.Abstract:
The effects of downfolding a Brillouin zone can open gaps and quench the kinetic energy by flattening bands. Quasiperiodic systems are extreme examples of this process, which leads to new phases and critical eigenstates. We analytically and numerically investigate these effects in a two-dimensional topological insulator with a quasiperiodic potential and discover a complex phase diagram. We study the nature of the resulting eigenstate quantum phase transitions; a quasiperiodic potential can make a trivial insulator topological and induce topological insulator-to-metal phase transitions through a unique universality class distinct from random systems. This wealth of critical behavior occurs concomitantly with the quenching of the kinetic energy, resulting in flat topological bands that could serve as a platform to realize the fractional quantum Hall effect without a magnetic field.read more
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References
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Journal ArticleDOI
Unconventional superconductivity in magic-angle graphene superlattices
Yuan Cao,Valla Fatemi,Shiang Fang,Kenji Watanabe,Takashi Taniguchi,Efthimios Kaxiras,Pablo Jarillo-Herrero +6 more
TL;DR: The realization of intrinsic unconventional superconductivity is reported—which cannot be explained by weak electron–phonon interactions—in a two-dimensional superlattice created by stacking two sheets of graphene that are twisted relative to each other by a small angle.
Journal ArticleDOI
Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
TL;DR: In this article, the quantum spin Hall (QSH) effect can be realized in mercury-cadmium telluride semiconductor quantum wells, a state of matter with topological properties distinct from those of conventional insulators.
Journal ArticleDOI
Scaling Theory of Localization: Absence of Quantum Diffusion in Two Dimensions
TL;DR: In this paper, it was shown that the conductance of disordered electronic systems depends on their length scale in a universal manner, and asymptotic forms for the scaling function were obtained for both two-dimensional and three-dimensional systems.
Journal ArticleDOI
Julia: A Fresh Approach to Numerical Computing
TL;DR: The Julia programming language as mentioned in this paper combines expertise from the diverse fields of computer science and computational science to create a new approach to numerical computing, which is designed to be easy and fast and questions notions generally held to be “laws of nature" by practitioners of numerical computing.
Journal ArticleDOI
Correlated insulator behaviour at half-filling in magic-angle graphene superlattices
Yuan Cao,Valla Fatemi,Ahmet Demir,Shiang Fang,Spencer Tomarken,Jason Luo,Javier Sanchez-Yamagishi,Kenji Watanabe,Takashi Taniguchi,Efthimios Kaxiras,Raymond Ashoori,Pablo Jarillo-Herrero +11 more
TL;DR: It is shown experimentally that when this angle is close to the ‘magic’ angle the electronic band structure near zero Fermi energy becomes flat, owing to strong interlayer coupling, and these flat bands exhibit insulating states at half-filling, which are not expected in the absence of correlations between electrons.
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