Abstract
We investigate transport in type-I/type-II Weyl semimetal heterostructures that realize effective black- or white-hole event horizons. We provide an exact solution to the scattering problem at normal incidence and low energies, both for a sharp and a slowly-varying Weyl cone tilt profile. In the latter case, we find two channels with transmission amplitudes analog to those of Hawking radiation. Whereas the Hawking-like signatures of these two channels cancel in equilibrium, we demonstrate that one can favor the contribution of either channel using a non-equilibrium state, either by irradiating the type-II region or by coupling it to a magnetic lead. This in turn gives rise to a peak in the two-terminal differential conductance which can serve as an experimental indicator of the artificial event horizon.
Highlights
Hawking radiation is the phenomenon whereby black holes slowly evaporate by emitting thermal radiation due to quantum fluctuations near the event horizon [1, 2]
Analogs of Hawking radiation can arise in other physical systems that are more amenable to experimental verification, featuring artificial event horizons sharing many similarities to their gravitational counterpart [3]
To the best of our knowledge, our work provides the first explicit calculation of physical observables in Weyl semimetal black hole analogs, and does so using a minimal model that captures all salient features of Weyl semimetals
Summary
Hawking radiation is the phenomenon whereby black holes slowly evaporate by emitting thermal radiation due to quantum fluctuations near the event horizon [1, 2]. In the case of a slowly-varying tilt profile with a linear horizon, for energies ω close to the Weyl node, counterpropagating particles tunnel through the effective horizon from inside the black hole region via two channels with probability. This paper is organized as follows: In Sec. 2, we introduce the continuum model for the Weyl semimetal heterostructure and in Sec. 3 we solve the scattering problem at normal incidence for the case of a fast or slow varying tilt profile. In the type-II phase, the zero-energy Fermi surface consists of electron and hole pockets touching at the Weyl nodes The connectivity of these pockets depends on the details of the tilting term. The low-energy expansions of the wavevectors and spinors are valid away from these extrema
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