First principles calculations of Sr-based fluoroperovskite compounds under applied pressure

The structural, electronic and thermoelectric properties of SrXF₃ (X?=?Li, Na, K, Rb) compounds are performed using first principle calculations. The mBJ-GGA method has been considered to obtain accurate band gaps. The present compounds are found to be thermodynamically stable under 0?GPa and 10?GPa. This stability has been determined using the standard enthalypy of formation. The band structures of the compounds display direct band-gap (Γ-Γ). The band gap has slightly increased for almost studied compounds under 10?GPa. The Boltzmann transport calculations are used to calculate and explain the thermoelectric properties as a function of temperature within the range 20–1500?K. The majority charge carriers of SrXF₃ compounds are holes rather than electrons. Under 10 GP pressure the SrLiF₃ compound is shifted from n-type to p-type doping, whereas SrKF₃ and SrRbF₃ are shifted from p-type to n-type. SrNaF₃ has p-type doping character under 0?GPa and 10?GPa. The Seebeck coeffiecient is found to decrease, whereas σ/τ and S² σ/τ increase for higher temperature. According to the figure of merit and the high S² σ/τ values for SrXF₃, promising thermoelectric applications are expected for the present compounds.