2000 character limit reached
Gapless insulating edges of dirty interacting topological insulators (1710.04232v2)
Published 11 Oct 2017 in cond-mat.str-el, cond-mat.dis-nn, cond-mat.mes-hall, and cond-mat.stat-mech
Abstract: We demonstrate that a combination of disorder and interactions in a two-dimensional bulk topological insulator can generically drive its helical edge insulating. We establish this within the framework of helical Luttinger liquid theory and exact Emery-Luther mapping. The gapless glassy edge state spontaneously breaks time-reversal symmetry in a `spin glass' fashion, and may be viewed as a localized state of solitons which carry half integer charge. Such a qualitatively distinct edge state provides a simple explanation for heretofore puzzling experimental observations. This phase exhibits a striking non-monotonicity, with the edge growing less localized in both the weak and strong disorder limits.