Magneto-transport in Pb_xSn_1-xSe Quantum Well

Pb_xSn1_-xSe (0.16<x<0.4) is a narrow gap semiconductor that exhibits a topological phase transition to a topological crystalline insulator (TCI) when the concentration of Sn increases. It is a valley degenerate topological system that can exhibit exotic quantum Hall effects and strong coupling between the crystal and electronic structures. Here we investigated the transport properties of PbEuSe/Pb_xSn_1-xSe/PbEuSe quantum wells, of which the thickness is 30 and 50nm and x=0.3. By doping Bismuth during the growth, we can efficiently tune the carrier type from p type to n type with carrier densities as low as 1E18cm^-3 and high mobility (>10000cm²/ (Vs)). We found out that the sample showed linear magnetoresistance starting at relatively low field (<1T). The slope of ΔR/R₀ is proportional to the mobility. We applied several model to explain this phenomenon. Further process like gating is also used to investigate the mechanism. With high mobility and low carrier density in the quantum well, it will be a great platform to study 2D quantum phenomenon in the landau quantized regime.