Transport properties related to two-dimensional surface states in gate-tunable Bi_0.1Pb_0.9Te thin films

We have achieved successfully the epitaxial grown Bi_0.1Pb_0.9Te on the SrTiO₃ substrates. By controlling the growth conditions and operating a back gate, the lattice distortion in Bi_0.1Pb_0.9Te has been observed. At low temperatures, it is expected to achieve the 2 % compressive strain threshold required for the realization of a theoretically predicted topological phase transition. Meanwhile, the data on metal-insulator transition and weak antilocalization (WAL) in the system reveal a transition from bulk transport dominance to surface state dominance, making it is possible to directly exploit the extraordinary properties of surface states. The Rashba splitting observed by ARPES and the magnetoconductivity being proportional only to the perpendicular component of the magnetic field demonstrate the two-dimensional (2D) nature of the surface states in Bi_0.1Pb_0.9Te thin films. In addition, the coexistence and competition of WAL and linear magnetoresistance (LMR) further reveal the correlation between spin-orbit interaction (SOI) and spin polarization effects with 2D surface states. These findings provide new insights into the electronic properties of PbTe-based materials and pave the way for future applications in spintronics and nanoelectronics.