Interaction-Driven Spontaneous Quantum Hall Effect on a Kagome Lattice.
Topological states of matter have been widely studied as being driven by an external magnetic field, intrinsic spin-orbital coupling, or magnetic doping. Here, we unveil an interaction-driven spontaneous quantum Hall effect (a Chern insulator) emerging in an extended fermion-Hubbard model on a kagome lattice, based on a state-of-the-art density-matrix renormalization group on cylinder geometry and an exact diagonalization in torus geometry. We first demonstrate that the proposed model exhibits an incompressible liquid phase with doublet degenerate ground states as time-reversal partners. The explicit spontaneous time-reversal symmetry breaking is determined by emergent uniform circulating loop currents between nearest neighbors. Importantly, the fingerprint topological nature of the ground state is characterized by quantized Hall conductance. Thus, we identify the liquid phase as a quantum Hall phase, which provides a "proof-of-principle" demonstration of the interaction-driven topological phase in a topologically trivial noninteracting band.
Department of Physics and Astronomy, California State University, Northridge, California 91330, USA.
W
W
Zhu
National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
Shou-Shu
SS
Gong
Department of Physics and Astronomy, California State University, Northridge, California 91330, USA.
Tian-Sheng
TS
Zeng
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Liang
L
Fu
Department of Physics and Astronomy, California State University, Northridge, California 91330, USA.
D N
DN
Sheng