Magnetic field induced strong valley polarization in the three dimensional topological semimetal LaBi

TL;DR

This study demonstrates that LaBi, a 3D topological semimetal, exhibits strong valley polarization induced by magnetic fields, achieving 60% polarization at low temperatures, which is significant for valleytronic applications.

Contribution

It reveals the magnetic field-induced valley polarization in LaBi and compares its efficiency with related compounds, highlighting its potential in valleytronics.

Findings

Achieved 60% valley polarization at 2 K

Valley polarization varies with magnetic field orientation

LaBi's polarization performance is comparable to bismuth

Abstract

LaBi is a three-dimensional rocksalt-type material with a surprisingly quasi-two-dimensional electronic structure. It exhibits excellent electronic properties such as the existence of nontrivial Dirac cones, extremely large magnetoresistance, and high charge-carrier mobility. The cigar-shaped electron valleys make the charge transport highly anisotropic when the magnetic field is varied from one crystallographic axis to another. We show that the electrons can be polarized effectively in these electron valleys under a rotating magnetic field. We achieved a polarization of 60% at 2 K despite the coexistence of three-dimensional hole pockets. The valley polarization in LaBi is compared to the sister compound LaSb where it is found to be smaller. The performance of LaBi is comparable to the highly efficient bismuth.