Flat band in disorder-driven non-Hermitian Weyl semimetals

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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2018-01-18

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Department of Applied Physics

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en

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1-5

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Physical Review B, Volume 97, issue 4

Abstract

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.

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DOI

10.1103/PhysRevB.97.041203

Citation

Zyuzin, A A & Zyuzin, A Y 2018, ' Flat band in disorder-driven non-Hermitian Weyl semimetals ', Physical Review B, vol. 97, no. 4, 041203, pp. 1-5 . https://doi.org/10.1103/PhysRevB.97.041203

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https://urn.fi/URN:NBN:fi:aalto-201808014180

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[article-cris] Perustieteiden korkeakoulu / SCI