Heat capacity and lattice anharmonicity in CdBIVC chalcopyrite compounds

Abstract The heat capacity at constant pressure of CdSiP2, CdGeP2, CdSnP2 and CdGeAs2 is measured in the temperature range from 300 to 500 K. The anharmonic contribution to the heat capacity is evaluated and it is shown that the degree of lattice anharmonicity decreases with increasing atomic weight of the constituent atoms of the compounds. Comparing the temperature variation of the heat capacity and of the thermal expansion coefficient some conclusions are made regarding the interatomic potential in the AIIBIVC compounds.