2018/04/30 by Shunyu Yao, Fei Song, Zhong Wang · 3 citations
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.other #cond-mat.quant-gas #cond-mat.str-el #physics.optics
paper · pdf · doi:10.1103/physrevlett.121.136802
published as Phys. Rev. Lett. 121, 136802 (2018) · 11 pages, 12 figures, including supplemental material
arxiv created 2018/09/25 · arxiv updated 2018/09/26
The relation between chiral edge modes and bulk Chern numbers of quantum Hall insulators is a paradigmatic example of bulk-boundary correspondence. We show that the chiral edge modes are not strictly tied to the Chern numbers defined by a non-Hermitian Bloch Hamiltonian. This breakdown of conventional bulk-boundary correspondence stems from the non-Bloch-wave behavior of eigenstates (non-Hermitian skin effect), which generates pronounced deviations of phase diagrams from the Bloch theory. We introduce non-Bloch Chern numbers that faithfully predict the numbers of chiral edge modes. The theory is backed up by the open-boundary energy spectra, dynamics, and phase diagram of representative lattice models. Our results highlight a unique feature of non-Hermitian bands and suggest a non-Bloch framework to characterize their topology.