Systematic first principle study of physical properties of Cd0.75Ti0.25Z (Z = S, Se,Te) magnetic semiconductors using mBJ functional

Abstract

Abstract The present article encompasses detailed investigations of structural, elastic, electronic properties to understand magnetic, optical and thermoelectric behaviors of Cd 0.75 Ti 0.25 Z (Z = S, Se, Te) alloys. The optimized structures have been used to reveal the thermodynamic stability in the ferromagnetic state, which is further confirmed in terms of the enthalpy of formation ( ΔH ) and the cohesive energy. The ferromagnetic and semiconducting natures are explained through the band structures (BS) and the density of states (DOS). The analysis of the exchange constants ( N 0 α and N 0 β ) reveals that N 0 β induces large splitting of Ti 3 d -states due to its more negative values compared with N 0 α , hence, strong p-d hybridization induces ferromagnetism because the exchange field overcomes the crystal field. Moreover, the magnetic moment of Ti reduces by inducing traces of magnetic moments on the nonmagnetic sites due to strong p-d hybridization. The computed Curie temperatures ( T c ) indicate that alloys show above room temperature ferromagnetism (RTFM). The potential optoelectronic applications are elucidated by comparing e 1 (0) and E g , which are related through Penn's model. The blue shift of the absorption in the visible region caused by Ti doping make the studied materials potential candidate for magneto-optical and solar cell technology. Although Ti doping degrades overall thermoelectric performance, however, increased power factor at low temperatures in Ti doped CdS evidences that the studied compounds may find potential thermoelectric device applications.