Ab initio Calculations on the Atomic and Electronic Structures of Oxygen- Doped Hexagonal Ge2Sb2Te5

Abstract

The atomic configurations, energetics, and electronic structures of oxygen doped hexagonal Ge2Sb2Te5 were investigated by using ab-initio calculations. Oxygen atoms or molecules were added at the possible interstitial or substitutional sites. The formation energies showed that both oxygen atoms and molecules would be spontaneously incorporated into hexagonal Ge2Sb2Te5. Oxygen atoms prefer forming bonds with Ge and Sb than with Te. The doped oxygen molecule was immediately dissociated into two oxygen atoms. The spontaneous incorporation of oxygen and dissociation of oxygen molecules are distinctly opposite to the nitrogen doping behavior in hexagonal Ge2Sb2Te5. (c) 2012 The Japan Society of Applied Physics