Elastic mechanical thermodynamic and thermoelectric properties of pristine and titanium doped Mg2Si: a density functional theory study

Abstract Herein, we report a systematic investigation of the effect of Titanium doping on the structural, elastic, mechanical, thermodynamic, and thermoelectric (TE) dynamics of Mg2Si Compounds using first-principle investigation. The present study has been carried out using the FP-LAPW (full potential linearized augmented plane wave)method as implemented in Wien2k code under mBJ exchange potentials. The investigations revealed that Mg2-xTixSi compounds have structural stability with cubic phase (Fm-3m symmetry) and possess degenerate semiconducting nature. The analysis of elastic constants revealed mechanical stability of the investigated compounds following Born criteria. Thermodynamic investigations have been carried out in the temperature range of 100 to 1500 K at zero pressure and the quantities like heat capacity, Debye temperature, Grüneisen constant, and thermal expansion coefficient have been critically analyzed. Lastly, the thermoelectric performance of Mg2-xTixSi compounds has been predicted by estimating the thermopower (S2σ) and thermoelectric figure of merit (zT) in the temperature range of 300 to 1500 K. The predicted value of zTmax for Mg2-xTixSi compound is 0.67 at 800 K for x = 0.25 titanium content, suggesting materials promising application for thermoelectric energy harvesting and mechanical devices.