2016/01/31 by Y. X. Zhao, Andreas P. Schnyder, Z. D. Wang · 2 citations
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.str-el #quant-ph
paper · pdf · doi:10.1103/physrevlett.116.156402
published as Phys. Rev. Lett. 116, 156402 (2016) · 4 pages, 1 figure and supplemental material, to be published in PRL
arxiv created 2016/04/07 · arxiv updated 2016/04/15
As PT and CP symmetries are fundamental in physics, we establish a unified topological theory of PT and CP invariant metals and nodal superconductors, based on the mathematically rigorous KO theory. Representative models are constructed for all nontrivial topological cases in dimensions d=1,2, and 3, with their exotic physical meanings being elucidated in detail. Intriguingly, it is found that the topological charges of Fermi surfaces in the bulk determine an exotic direction-dependent distribution of topological subgap modes on the boundaries. Furthermore, by constructing an exact bulk-boundary correspondence, we show that the topological Fermi points of the PT and CP invariant classes can appear as gapless modes on the boundary of topological insulators with a certain type of anisotropic crystalline symmetry.