Quantum Oscillations in Trigonal PtBi_1.6 Single Crystals

Transition-metal dichalcogenide PtBi₂ is known to form multiple structures with extreme large magnetoresistance (XMR). We have successfully grown high-quality PtBi_1.6 single crystals with the trigonal structure. In addition to the XMR effect, the magnetization exhibits de Haas–van Alphen (dHvA) oscillations at low temperatures. Through Fourier transformation, we identify two oscillation frequencies F_δ = 4 T and F_α = 39 T with the sign of Zeeman splitting. Using Lifshitz–Kosevich (LK) formula to fit experimental data, we obtain the effective masses (m^*_δ = 0.092m₀ and m^*_α = 0.189m₀) and Berry phases (Φ_Bδ = (0.82 + 2δ)π and Φ_Bα = (0.86 + 2δ)π) for both δ and α bands. The results indicate the trigonal PtBi_1.6 has non-trivial topological properties.