Experimental study of transport properties of Weyl semimetal LaAlGe thin films grown by molecular beam epitaxy

TL;DR

This study investigates the crystal structure and magneto-transport properties of LaAlGe thin films, revealing positive magnetoresistance and electron-dominated conduction, advancing understanding of Weyl semimetal behavior in thin film form.

Contribution

It provides the first detailed analysis of LaAlGe thin films grown by molecular beam epitaxy, highlighting their transport properties and magnetoresistance behavior.

Findings

Positive unsaturated magnetoresistance observed

Electron-dominated conduction confirmed by Hall measurements

Charge carrier density around 9.68×10^21 cm^(-3) at room temperature

Abstract

Rare earth compounds display diverse electronic, magnetic, and magneto-transport properties. Recently these compounds of the type RAlGe (R = La, Ce, Pr) have been shown to exhibit Weyl semimetallic behavior. In this work, we have investigated the crystal structure, electronic, and magneto-transport properties of the Weyl semimetal LaAlGe thin films grown by molecular beam epitaxy. The temperature dependence of longitudinal resistivity at different magnetic fields is discussed. Observations of magnetoresistances and Hall effect at different temperatures and their evolution with magnetic field up to 6 T are also discussed with relevant mechanisms. We have observed positive unsaturated magnetoresistances, with a small quadratic contribution at low temperatures, which tends to saturate at higher fields. The Hall measurements confirm the electron-dominated semimetallic conduction with an average charge carrier density of ~ 9.68*10^21 cm^(-3) at room temperature.