Transport and material properties of doped BiSbX topological insulator films grown by physical vapor deposition

Topological Insulator (TI) BiSb is a promising material for spin-orbit torque (SOT) devices because of its high spin Hall angle, relatively higher electrical conductivity, and can be produced at room temperature by physical vapor deposition. In this work, we systematically investigate the effects of doping BiSb with several dopants. We found that doping with elemental dopants does not change the bulk conductivity, but doping with metal-nitride or metal-oxide molecular dopants can substantially increase or decrease BiSb’s bulk film conductivity with minor impacts on its TI properties. Furthermore, doping can significantly improve other TI film material properties such as increased melting point and film hardness, producing smaller grain sizes with improved interfacial roughness, and enhanced (012) film growth texture, all of which can contribute to enhanced atomic migration resistance in and out of the BiSb layer. Thus, our results open a path for using doped BiSb in integrated SOT devices