Spinless charged excitation at the interface between a conventional topological insulator and a topological Mott insulator
arXiv:2607.14221
The paper uses density-matrix renormalization group simulations of a triangular-lattice Hofstadter-Hubbard model with a spatially varying interaction to study the interface between an integer quantum Hall insulator and a chiral spin liquid, revealing a bound spinless charged excitation at the interface.
Abstract
We investigate the interface separating two topologically distinct insulating phases of matter using extensive density-matrix renormalization group calculations to study the triangular-lattice Hofstadter-Hubbard model with a spatially varying interaction strength, chosen to realize both integer quantum Hall and chiral spin liquid states in different spatial regions. We find that the integer quantum Hall-chiral spin liquid interface hosts a spinless charged excitation that is bound to the interface. This mode at the interface is identified through charge and spin pumping, and by direct calculations of low-lying excited states. We also characterize bulk excitations in both phases, finding evidence for fractionalization in the chiral spin liquid and for spin-triplet exciton formation in the integer quantum Hall phase.
5+1 pages, 5+2 figures