Observation of surface dominated topological transport in strained semimetallic ErPdBi thin films

Artikel i vetenskaplig tidskrift, 2020

In this Letter, we present experimental observation of surface-dominated transport properties in [110]-oriented strained (∼1.6%) ErPdBi thin films. The resistivity data show typical semi-metallic behavior in the temperature range of 3 K ≤ T ≤ 350 K with a transition from semiconductor- to metal-like behavior below 3 K. The metallic behavior at low temperature disappears entirely in the presence of an external magnetic field >1 T. The weak-antilocalization (WAL) effect is observed in magneto-conductance data in the low magnetic field region and follows the Hikami-Larkin-Nagaoka (HLN) model. HLN fitting estimated single coherent channel, i.e., α ∼-0.51 at 1.9 K, and the phase coherence length (Lφ) shows the Lφ ∼T-0.52 power law dependence on temperature in the range of 1.9 K-10 K, indicating the observation of 2D WAL. Shubnikov-de Haas (SdH) oscillations are observed in magneto-resistance data below 10 K and are fitted to standard Lifhsitz Kosevich theory. Fitting reveals the effective mass of charge carriers ∼0.15 me and a finite Berry phase of 0.86π± 0.16. The sheet carrier concentration and mobility of carriers estimated using SdH data are ns ∼1.35 × 1012 cm-2 and μs = 1210 cm2 V-1 s-1, respectively, and match well with the data measured using the Hall measurement at 1.9 K to be n ∼1.22 × 1012 cm-2, μ = 1035 cm2 V-1 s-1. These findings indicate the non-trivial nature and surface-dominated transport properties of strained (110) ErPdBi thin films at low temperatures.