Symmetry breaking and the fermionic fractional Chern insulator in topologically trivial bands

Article

关键词: QUANTIZED HALL CONDUCTANCE;    STATES;    REALIZATION;    FERROMAGNET;    INVARIANT;    LATTICE;    MODEL;   

DOI  :  10.1103/PhysRevB.97.085108

来源: SCIE

【 摘 要 】

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 rho(CO) = 2/3 particles per site, then dope the model to higher densities rho = rho(CO) + v/6. At v = 1/3,2/5 (rho = 13/18,11/15) we observe definitive signatures of both CO and the FQH effect-a sharply peaked static structure factor, gapped and degenerate energy spectrum, and fractionally quantized Hall conductivity sigma(H) = 1/3,2/5 in units of e(2)/h-over a range of all model parameters. We thus obtain direct evidence for fermionic SBT order of FQH type in topologically trivial bands.

【 授权许可】

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