Observation of pseudo two dimensional electron transport in the rock salt type topological semimetal LaBi

TL;DR

This study reports pseudo two-dimensional electron transport in LaBi, a topological semimetal, where bulk states mimic surface state behavior, leading to highly anisotropic magnetoresistance with large amplitude.

Contribution

It reveals that bulk states in LaBi can produce surface-like transport phenomena, challenging the traditional distinction between surface and bulk conduction in topological materials.

Findings

Observation of surface state-like behavior in bulk electrons

Angle-dependent quantum oscillations confirm bulk origin

Magnetoresistance shows strong anisotropy (~10^5 %)

Abstract

Topological insulators are characterized by an inverted band structure in the bulk and metallic surface states on the surface. In LaBi, a semimetal with a band inversion equivalent to a topological insulator, we observe surface state like behavior in the magnetoresistance. The electrons responsible for this pseudo two dimensional transport, however, originate from the bulk states rather topological surface states, which is witnessed by the angle dependent quantum oscillations of the magnetoresistance and ab initio calculations. As a consequence, the magnetoresistance exhibits strong anisotropy with large amplitude (~ 10^5 %).