Electronic structure of monolayers of group V atoms: Puckering and spin orbit interaction in nano-slabs (1412.2160v1)

Abstract: Inspired by the observation of mass less Dirac particles associated with low energy excitations of 2-dimensional (2D) honeycomb (HC) lattices of group IV atoms (C, Si, Ge, Sn) near the Dirac points (DPs) and spin-orbit interaction (SOI) induced gaps at the DPs, we have investigated the electronic structure of 2D HC lattices of group V atoms (As, Sb, Bi). Here also one sees DPs at the K points in the Brillouin zone for both planar (flat) and puckered sheets. Unlike the group IV systems the Fermi energy in group V systems lies above the DPs. The flat sheets are metallic but undergo structural distortions to form puckered sheets that are semiconducting. SOI profoundly alters the band structure, opens up gaps at the DPs, and in binary systems BiSb and SbAs gives large Rashba-type spin splitting. Nano-slabs of group V atoms show excellent thermoelectric properties, particularly in the hole-doped regime.