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

Abstract

Rare earth compounds display diverse electronic, magnetic, and magnetotransport 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 and electronic and magnetotransport 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 the Hall effect at different temperatures and their evolution with magnetic fields 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 tend to saturate at higher fields. The Hall measurements confirm the electron-dominated semimetallic conduction with an average charge carrier density of ∼9.68 × 1021 cm−3 at room temperature.