Topological exceptional surfaces in non-Hermitian systems with parity-time and parity-particle-hole symmetries

Ryo Okugawa; Takehito Yokoyama

doi:10.1103/PhysRevB.99.041202

Topological exceptional surfaces in non-Hermitian systems with parity-time and parity-particle-hole symmetries

Ryo Okugawa, Takehito Yokoyama

Advanced Institute for Materials Research (AIMR)

Research output: Contribution to journal › Article › peer-review

114 Citations (Scopus)

Abstract

We study a topological band degeneracy in non-Hermitian systems with parity-time (PT) and parity-particle-hole (CP) symmetries. In d-dimensional non-Hermitian systems, it is shown that (d-1)-dimensional exceptional surfaces can appear from band touching thanks to PT or CP symmetry. We investigate the topological stability and zero-gap quasiparticles for the exceptional surfaces due to the band degeneracy. We also demonstrate the band degeneracy by using lattice models of a topological semimetal and a superconductor.

Original language	English
Article number	041202
Journal	Physical Review B
Volume	99
Issue number	4
DOIs	https://doi.org/10.1103/PhysRevB.99.041202
Publication status	Published - 2019 Jan 24

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics

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10.1103/PhysRevB.99.041202

Cite this

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title = "Topological exceptional surfaces in non-Hermitian systems with parity-time and parity-particle-hole symmetries",

abstract = "We study a topological band degeneracy in non-Hermitian systems with parity-time (PT) and parity-particle-hole (CP) symmetries. In d-dimensional non-Hermitian systems, it is shown that (d-1)-dimensional exceptional surfaces can appear from band touching thanks to PT or CP symmetry. We investigate the topological stability and zero-gap quasiparticles for the exceptional surfaces due to the band degeneracy. We also demonstrate the band degeneracy by using lattice models of a topological semimetal and a superconductor.",

author = "Ryo Okugawa and Takehito Yokoyama",

note = "Funding Information: This work was supported by World Premier International Reserach Center Initiative (WPI), MEXT, Japan, JPSJ Grant-in-Aid Scientific Research on Innovative Areas “Discrete Geometric Analysis for Materials Design” (Grant No. 17H06460) and “Nano Spin Conversion Science” (Grant No. JP17H05179), and the JSPS-EPSRC Core-to-Core program “Oxide Superspin.” Publisher Copyright: {\textcopyright} 2019 American Physical Society.",

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Topological exceptional surfaces in non-Hermitian systems with parity-time and parity-particle-hole symmetries

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