Spinless Charged Excitation at the Interface between a Conventional Topological Insulator and a Topological Mott Insulator
Phys. Rev. Lett. 137, 196501 – Published 2 November, 2026
DOI: https://doi.org/10.1103/p38y-wyrj
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.
