Chirality-dependent electron transport in Weyl semimetal p–n–p junctions

Abstract

Recently discovered Weyl semimetals have received considerable research interest due to the exotic Weyl fermion-like excitations and the nontrivial π Berry phase near the band degenerate points. Here we show that by constructing a Weyl semimetal p–n–p junction and restricting Weyl fermions into closed orbits with electric and magnetic confinements, the Berry phase acquired by the Weyl fermions can be controlled flexibly. This brings out two effects on electron transport through the junction: when the Berry phase is integer multiples of π an obvious phase shift is observed in the transmission map, whereas for non-integer ones of Berry phase the transmission shows strong chirality dependence and a large chiral or valley-level splitting can be induced. Utilizing this chirality splitting, we further propose a new method to measure the Berry phase in Weyl semimetals, which shows accuracy for various potential profiles and has practical applications in experiments.