The dHvA effect in Sn-doped PbTe topological crystalline insulator.

Abstract

We report the synthesis, electrical transport, magnetotransport, and high-field torque magnetometry studies of the topological crystalline insulator Sn_xPb1-xTe (x= 0, 0.2, and 0.4). This material undergoes a topological phase transition from trivial to non-trivial at a critical doping ofxc= 0.35. The resistivity increases with applied magnetic field, displaying positive magnetoresistance (MR), which reaches up to 4500% at 14 T for PbTe. However, we did not observe Shubnikov-de Haas oscillations in the MR data. To observe quantum oscillations and explore the Fermi surface topology of this material, we conducted torque magnetometry experiments on samples both below (x= 0.2) and above (x= 0.4) the critical dopingxc= 0.35 with applied magnetic fields up to 35 T. The torque signal from both samples revealed clear de Haas-van Alphen (dHvA) oscillations above 15 T. These oscillations exhibited single dominant frequencies of 90 T forx= 0.2 and 51 T forx= 0.4, providing insights into the Fermi surface properties. Angular and temperature-dependent analyses of the dHvA oscillations were performed using Lifshitz-Kosevich theory to extract key physical parameters of the Fermi surface. Berry phase analysis based on Landau level fan diagrams revealed non-zero values for bothx= 0.2 andx= 0.4, indicating non-trivial topological features. This study provides detailed insights into the quantum oscillations and Fermi surface properties of Sn-doped PbTe/Se compounds, contributing to a deeper understanding of topological crystalline materials and their broader implications for topological physics.