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Topological Lattice Models with Constant Berry Curvature

by Daniel Varjas, Ahmed Abouelkomsan, Kang Yang, Emil J. Bergholtz

Submission summary

As Contributors: Emil Bergholtz · Daniel Varjas
Preprint link: scipost_202107_00047v1
Code repository: https://zenodo.org/record/5102818#.YPk3hRMza3I
Date submitted: 2021-07-22 14:31
Submitted by: Varjas, Daniel
Submitted to: SciPost Physics
Academic field: Physics
Specialties:
  • Condensed Matter Physics - Theory
Approaches: Theoretical, Computational

Abstract

Band geometry plays a substantial role in topological lattice models. The Berry curvature, which resembles the effect of magnetic field in reciprocal space, usually fluctuates throughout the Brillouin zone. Motivated by the analogy with Landau levels, constant Berry curvature has been suggested as an ideal condition for realizing fractional Chern insulators. Here we show that while the Berry curvature cannot be made constant in a topological two-band model, lattice models with three or more degrees of freedom per unit cell can support exactly constant Berry curvature. However, contrary to the intuitive expectation, we find that making the Berry curvature constant does not always improve the properties of bosonic fractional Chern insulator states. In fact, we show that an "ideal flatband" cannot have constant Berry curvature.

Current status:
Editor-in-charge assigned


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Submission scipost_202107_00047v1 on 22 July 2021

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