Thermodynamic and stoichiometric stability of the Cd-terminated CdTe (111) surface

Abstract

Employing ab initio thermodynamics calculations, we elucidate for the first time the effects of growth conditions on the reconstruction phase diagram of the polar Cd-terminated CdTe (111) surface and resolve an existing experimental controversy of the low-temperature reconstruction under Te-rich conditions. We demonstrate that the Cd-vacancy $(2\ifmmode\times\else\texttimes\fi{}2)$ reconstruction is the most stable configuration in the allowed range of the Te chemical potential. Under Te-rich conditions, however, the calculations reveal a transition from a high-temperature semiconducting ($2\ifmmode\times\else\texttimes\fi{}2$) to a low-temperature metallic ($1\ifmmode\times\else\texttimes\fi{}1$)-Te${}_{n}$ reconstruction consisting of $n$ Te adlayers forming a spiral trigonal structure. We also predict the temperature and pressure dependence of the Te thickness adlayer, which has remained experimentally unresolved.