Flat band in disorder-driven non-Hermitian Weyl semimetals

A. A. Zyuzin, A. Yu Zyuzin

Tutkimustuotos: LehtiartikkeliArticleScientificvertaisarvioitu

146 Sitaatiot (Scopus)
374 Lataukset (Pure)

Abstrakti

We study the interplay of disorder and band-structure topology in a Weyl semimetal with a tilted conical spectrum around the Weyl points. The spectrum of particles is given by the eigenvalues of a non-Hermitian matrix, which contains contributions from a Weyl Hamiltonian and complex self-energy due to electron elastic scattering on disorder. We find that the tilt-induced matrix structure of the self-energy gives rise to either a flat band or a nodal line segment at the interface of the electron and hole pockets in the bulk band structure of type-II Weyl semimetals depending on the Weyl cone inclination. For the tilt in a single direction in momentum space, each Weyl point expands into a flat band lying on the plane, which is transverse to the direction of the tilt. The spectrum of the flat band is fully imaginary and is separated from the in-plane dispersive part of the spectrum by the "exceptional nodal ring" where the matrix of the Green's function in momentum-frequency space is defective. The tilt in two directions might shrink a flat band into a nodal line segment with "exceptional edge points." We discuss the connection to the non-Hermitian topological theory.

AlkuperäiskieliEnglanti
Artikkeli041203
Sivut1-5
JulkaisuPhysical Review B
Vuosikerta97
Numero4
DOI - pysyväislinkit
TilaJulkaistu - 18 tammik. 2018
OKM-julkaisutyyppiA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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