Topological behavior and Zeeman splitting in trigonal PtBi2-x single crystals

Abstract

Transition-metal dipnictide PtBi2 exhibits rich structural and physical properties with topological semimetallic behavior and extremely large magnetoresistance (XMR) at low temperatures. We have investigated the electrical and magnetic properties of trigonal-phase PtBi2-x single crystals with x ~ 0.4. Profound de Haas–van Alphen (dHvA) and Shubnikov-de Haas (SdH) oscillations are observed. Through fast Fourier transformation (FFT) analyses, four oscillation frequencies are extracted, which result from α, β, γ, and δ bands. By constructing the Landau fan diagram for each band, the Berry phase is extracted demonstrating the non-trivial nature of the α, β, and δ bands. Despite Bi deficiency, we observe the Zeeman splitting in dHvA and SdH oscillations under moderate magnetic field and the moderate Landé g factor (4.97–6.48) for the α band. Quantitative analysis of the non-monotonic field dependence including the sign change of the Hall resistivity suggests that electrons and holes in our system are not perfectly compensated thus not responsible for the XMR effect.