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arXiv · 2201.05616

Mesoscopic transport signatures of disorder-induced non-Hermitian phases

Benjamin Michen·Jan Carl Budich
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Abstract

We investigate the impact on basic quantum transport properties of disorder-induced exceptional points (EPs) that emerge in a disorder-averaged Green's function description of two-dimensional (2D) Dirac semimetals with spin- or orbital-dependent potential scattering. Remarkably, we find that EPs may promote the nearly vanishing conductance of a finite sample at the Dirac point to a sizable value that increases with disorder strength. This striking behavior exhibits a strong directional anisotropy that is closely related to the Fermi arcs connecting the EPs. We corroborate our results by numerically exact simulations, thus revealing the fingerprints of characteristic non-Hermitian spectral features also on the localization properties of the considered systems. Finally, several candidates for the experimental verification of our theoretical analysis are discussed, including disordered electronic square-net materials and cold atoms in spin-dependent optical lattices.

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Benjamin Michen, Jan Carl Budich. 2022-01-14. Mesoscopic transport signatures of disorder-induced non-Hermitian phases. https://doi.org/10.1103/physrevresearch.4.023248

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