First-Principle Calculations of Fundamental Properties of AgGaTe2, AgInTe2 and Their Mixed Crystals AgIn1-xGaxTe2

摘要

In this work, we studied the structural, electronic, elastic and thermodynamic properties of the ternary AgGaTe2 and AgInTe2 chalcopyrite semiconductors and their mixed crystals AgIn1-xGaxTe2 using the full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). The optimized equilibrium structural parameters (a, c and u) are in good agreement with the experimental and theoretical results obtained by other researchers. The electronic-structure calculations show that the ternary compounds are direct band gap semiconductors. We modeled the AgIn1-xGaxTe2 alloys at some selected compositions with ordered structures described in terms of periodically repeated supercells. The effects of the composition (x) on lattice parameters, bulk moduli and band gaps were investigated. Furthermore, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing Delta Hm as well as the phase diagram.