First-principles calculations of optoelectronic and thermoelectric properties of HgGa2S4 chalcopyrite under pressure effect

Abstract

The optoelectronic and thermoelectric properties of HgGa2S4chalcopyrite under applied pressures were studied by the Generalized Gradient Approximation (GGA) and the modified Becke-Johnson (mBJ) approaches and the Boltzmann transport theory. The structural calculations show that the optimized lattice constants decrease with the applied pressure. The mBJ-based results indicate that the band gap energy and the static dielectric constants increase with the applied pressure. The optimized lattice constants and the optical band gap under different pressures are in close agreement with the experimental values. The two none-zero dielectric tensor components show significant anisotropy between the perpendicular and parallel components. With increasing pressure, the plasma frequency shifts to the higher energies; it makes this material a good candidate for optoelectronic devices. The results show that a high thermoelectric efficiency can be achieved through controlling the carrier concentration and pressure. Highfigure of merit of 0.98 was obtained for the p-type HgGa2S4 chalcopyrite.