Non-Hermitian higher-order Weyl semimetals

@article{Ghorashi2021NonHermitianHW,
  title={Non-Hermitian higher-order Weyl semimetals},
  author={Sayed Ali Akbar Ghorashi and Tianhe Li and Masatoshi Sato},
  journal={Physical Review B},
  year={2021}
}
We study non-Hermitian higher-order Weyl semimetals (NHHOWSMs) possessing real spectra and having inversion I (I-NHHOWSM) or time-reversal symmetry T (T -NHHOWSM). When the reality of bulk spectra is lost, the NHHOWSMs exhibit various configurations of surface Fermi Arcs (FAs) and Exceptional Fermi Rings (EFRs), providing a setup to investigate them on an equal footing. The EFRs only appear in the region between 2nd-order WNs. We also discover Weyl nodes originating from non-Hermicity, called… 
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References

SHOWING 1-10 OF 68 REFERENCES
Non-Hermitian higher-order Dirac semimetals
In this article we study 3D non-Hermitian higher-order Dirac semimetals (NHHODSMs). Our focus is on C4-symmetric non-Hermitian systems where we investigate inversion (I) or time-reversal (T )…
Higher-Order Weyl Semimetals.
TLDR
A new type of Weyl node is identified that can be identified as a transition in momentum space in which both the Chern number and a higher order topological invariant change are identified.
Non-Hermitian higher-order topological states in nonreciprocal and reciprocal systems with their electric-circuit realization
  • M. Ezawa
  • Physics, Mathematics
    Physical Review B
  • 2019
A prominent feature of some one-dimensional non-Hermitian systems is that all right-eigenstates of the non-Hermitian Hamiltonian are localized in one end of the chain. The topological and trivial…
Non-Hermitian extensions of higher-order topological phases and their biorthogonal bulk-boundary correspondence
Non-Hermitian Hamiltonians, which describe a wide range of dissipative systems, and higher-order topological phases, which exhibit novel boundary states on corners and hinges, comprise two areas of…
Second-Order Topological Phases in Non-Hermitian Systems.
A d-dimensional second-order topological insulator (SOTI) can host topologically protected (d-2)-dimensional gapless boundary modes. Here, we show that a 2D non-Hermitian SOTI can host zero-energy…
Floquet second-order topological insulators in non-Hermitian systems
Second-order topological insulator (SOTI) is featured with the presence of $(d\ensuremath{-}2)$-dimensional boundary states in $d$-dimension systems. The non-Hermiticity induced breakdown of…
Strong and fragile topological Dirac semimetals with higher-order Fermi arcs
TLDR
It is discovered that strong and fragile topological Dirac semimetals exhibit one-dimensional (1D) higher-order hinge Fermi arcs (HOFAs) as universal, direct consequences of their bulk 3D Dirac points, revealing condensed matter Dirac fermions to be higher- order topological.
Observation of a phononic higher-order Weyl semimetal
TLDR
This study reports a higher-order Weyl semimetal (HOWSM) in a phononic system that exhibits topologically protected boundary states in multiple dimensions, and establishes the fundamental connection between higher- order topology and Weyl physics in crystalline materials.
Classification of Exceptional Points and Non-Hermitian Topological Semimetals.
TLDR
This classification of generic topologically stable exceptional points is presented according to two types of complex-energy gaps and fundamental symmetries of charge conjugation, parity, and time reversal and reveals unique non-Hermitian gapless structures with no Hermitian analogs.
Topological Phases of Non-Hermitian Systems
Recent experimental advances in controlling dissipation have brought about unprecedented flexibility in engineering non-Hermitian Hamiltonians in open classical and quantum systems. A particular…
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