Sb-terminated InAs(001)-(2x4) and (2x8) studied using scanning tunneling microscopy and ab initio density functional theory

摘要

We have studied the structure of MBE-grown InAs(001)-(2x4) surfaces exposed to low Sb_2 fluxes by scanning tunneling microscopy (STM) and ab initio density functional theory (DFT). Experimentally, we observe an Sb-terminated α2(2x4) phase over a wide range of temperatures (400-510°C) for low Sb_2 flux (<0.1 ML/s), whereas temperature and As_2 flux must be carefully controlled to achieve the same As-terminated surface structure. At lower temperatures, we observe indications of an Sb-terminated (2x8) symmetry surface phase, and we report briefly on its proposed structure and stability, as well as its possible role in subsequent formation of the Sb-terminated (1x3) phase found at typical Sb_2 fluxes used during heterostructure growth.