Electronic, vibrational and thermodynamic properties of Ca10(AsO4)6(OH)2: first principles study

Abstract

The electronic, vibrational and thermodynamic properties of johnbaumite (AHAP Ca 10 (AsO 4 ) 6 (OH) 2 ) have been performed by First principles approach. AHAP is an indirect band-gap material of 3.98 eV. The calculated phonon dispersion indicates that AHAP is stable. For AHAP, the optical vibrational modes at the Γ -point are assigned: 21E1 + 19A + 22E2 + 24B, and the frequencies agree well with available experimental data. The largest LO-TO phonon frequency splitting occurs at A mode (770.2 cm -1 to 807.6 cm -1) . Finally, the thermodynamic properties of AHAP are predicted.