Electronic scattering, focusing, and resonance by a spherical barrier in Weyl semimetals

TL;DR

This paper investigates how Weyl electrons scatter off a spherical barrier, revealing regimes of focusing, resonance, and density aggregation that are relevant for electronic transport and lensing in Weyl semimetals.

Contribution

It provides a detailed analysis of scattering phenomena in Weyl semimetals, including classical and quantum regimes, with insights into focusing effects and resonance behaviors.

Findings

Strong forward scattering preference observed.

Focusing effects and optical caustics in the quasiclassical regime.

Resonance-induced electron density aggregation inside the barrier.

Abstract

We solve the Weyl electron scattered by a spherical step potential barrier. Tuning the incident energy and the potential radius, one can enter both quasiclassical and quantum regimes. Transport features related to far-field currents and integrated cross sections are studied to reveal the preferred forward scattering. In the quasiclassical regime, a strong focusing effect along the incident spherical axis is found in addition to optical caustic patterns. In the quantum regime, at energies of successive angular momentum resonances, a polar aggregation of electron density is found inside the potential. The findings will be useful in transport studies and electronic lens applications in Weyl systems.