2020/08/02 by Chang-An Li, Bo Fu, Zi-Ang Hu +2 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.125.166801
published as Phys. Rev. Lett. 125, 166801 (2020) · 6+10 pages, 3+5 figures
arxiv created 2020/08/02 · arxiv updated 2020/10/21
We investigate disorder-driven topological phase transitions in quantized electric quadrupole insulators. We show that chiral symmetry can protect the quantization of the quadrupole moment qxy, such that the higher-order topological invariant is well-defined even when disorder has broken all crystalline symmetries. Moreover, nonvanishing qxy and consequent corner modes can be induced from a trivial insulating phase by disorder that preserves chiral symmetry. The critical points of such topological phase transitions are marked by the occurrence of extended boundary states even in the presence of strong disorder. We provide a systematic characterization of these disorder-driven topological phase transitions from both bulk and boundary descriptions.