2019/12/23 by Haoran Xue, Qiang Wang, Baile Zhang +1 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #physics.optics
paper · pdf · doi:10.1103/physrevlett.124.236403
published as Phys. Rev. Lett. 124, 236403 (2020)
arxiv created 2019/12/23 · arxiv updated 2020/06/17
Non-Hermitian systems, which contain gain or loss, commonly host exceptional point degeneracies rather than the diabolic points found in Hermitian systems. We present a class of non-Hermitian lattice models with symmetry-stabilized diabolic points, such as Dirac or Weyl points. They exhibit non-Hermiticity-induced phenomena previously existing in the Hermitian regime, including topological phase transitions, Landau levels induced by pseudo-magnetic fields, and Fermi arc surface states. These behaviors are controllable via gain and loss, with promising applications in tunable active topological devices.