Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session P44: Topological Protection in Correlated Electron Systems 2
2:30 PM–5:30 PM,
Wednesday, March 7, 2018
LACC Room: 504
Sponsoring Unit: DCMP
Chair: Saurabh Maiti, University of Massachusetts Amherst
Abstract: P44.00006 : Symmetry breaking and fermionic fractional Chern insulator in topologically trivial bands*
3:30 PM–3:42 PM
View Presentation Abstract
We describe a mechanism by which fermions in topologically trivial bands can form correlated states exhibiting a fractional quantum Hall (FQH) effect upon introduction of strong repulsive interactions. These states are solid-liquid composites, in which a FQH liquid is induced by the formation of charge order (CO), following a recently proposed paradigm of symmetry-breaking topological (SBT) order [Phys. Rev. Lett. 113, 216404 (2014)]. We devise a spinless fermion model on a triangular lattice, featuring a topologically trivial phase when interactions are omitted. Adding strong short-range repulsion, we first establish a repulsion-driven CO phase at density ρCO = 2/3 particles per site, then dope the model to higher densities ρ = ρCO + ν/6. At ν=1/3,2/5 (ρ=13/18,11/15), we observe definitive signatures of both CO and the FQH effect --- sharply peaked static structure factor, gapped and degenerate energy spectrum and fractionally quantized Hall conductivity σH = 1/3,2/5 in units of e2/h --- over a range of all model parameters. We thus obtain the first strong evidence for fermionic SBT order in topologically trivial bands.
*This work was partially supported by the Boston University Center for Non-Equilibrium Systems and Computation.
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