Electrical and magneto-transport properties of GdPdBi half-Heusler thin films

Abstract

We report the electrical and magneto-transport properties of [110]-oriented equiatomic GdPdBi thin films grown by pulsed laser deposition. Temperature-dependent resistivity measurements over the temperature range 3.5 K ≤ T ≤ 300 K indicate semiconducting behavior, with an activation energy gap of ∼10.2 meV, lower than the bulk bandgap (∼70 meV), suggesting strain-induced band narrowing in the thin films. Additionally, deviations from Nyquist behavior indicate electron–phonon scattering as the primary dephasing mechanism. A low-field cusp in the magneto-resistance, resembling weak anti-localization, is observed and attributed to three-dimensional bulk spin–orbit coupling, as confirmed by angle-dependent magneto-conductance measurements. The first-principles calculations confirm that a 1.2% biaxial strain reduces the bandgap from approximately 100 meV (unstrained) to 26 meV (strained), consistent with the experimental trend, and further indicate that the applied strain in GdPdBi induces the onset of band inversion. These findings provide insight into the transport properties and band structure of the GdPdBi half-Heusler thin films.