Exploring the Thermoelectric Potential of Trigonal MgS2: A Computational Investigation Using DFT and Boltzmann Transport Theory

Abstract

There has been a shift toward the development of cost-effective and environmentally friendly technologies, due to increased energy demand and attendant environmental degradations. Among these technologies, significant progress has been made in the field of thermoelectricity. Thermoelectric materials are recognized for their proficiency in converting waste heat energy into electricity, with their efficiency commonly assessed using the ZT (Fig. of merit) value.. This study investigates the thermoelectric properties of chalcogenide magnesium sulfide (MgS2), with trigonal lattice structure, using Density Functional Theory (DFT) in conjunction with the Boltzmann Transport Theory. The initial assessment of structural and thermoelectric properties employs the Generalized Gradient Approximation (GGA) based on the Perdew–Burke–Ernzerhof approximation (GGA-PBE).

The results indicate that the studied compounds exhibit characteristics of a p-type semiconductor. The structural confirmation of MgS2 reveals a trigonal configuration. The absolute value of the Seebeck coefficient demonstrates an increase with rising temperature across the measured range (100-400K). Simultaneously, the electrical conductivity exhibits a monotonically decreasing trend with increasing temperature, indicative of degenerating conduction behaviour. The power factor exhibits an upward trajectory with increasing temperature, consequently leading to an augmented dimensionless Fig. of merit ZT. The maximum ZT value observed for MgS2 is 0.057.