Phosphorus-Doped SnTe-Type Needle-like Crystals: Band Structure Modifications and Electronic Properties

SnTe has recently emerged as a 3D crystalline topological insulator exhibiting band inversion at the L point where certain crystalline symmetries allow the protection of robust topological surface states. Synthesis and development of new Dirac materials by disturbing the SnTe symmetry was accomplished by substitution of a Sn vacancy by P that maintains the intrinsic band inversion at the L point but also the direct bandgap reduction upon the incorporation of spin orbit coupling. The exotic morphology of the synthesized P-doped SnTe microneedles produces signal amplification arising from the topological surface states due to the alteration of surface area to volume ratio. Moreover, the modified effective mass, lattice imperfection, and conductivity results in a large memory window ∼3.1 V for field effect transistors accompanied by a large change in current within a certain potential range.