Thermoelectric, Magneto-Optic Properties and Magnetocaloric Effect of PbS Doped with Mn2+ Ions

In this work, we have investigated the structural, electronic, magneto-optic, magnetocaloric and thermoelectric properties of Mn-doped PbS through the first-principles density functional calculations and Monte Carlo simulation. We have determined the structural parameters using GGA approximation. The structural parameters we obtained are in reasonable agreement with the available theoretical data. Regarding the electronic, magnetic-optic and thermoelectric properties, we used GGA + U, and mBJ-GGA approximations. PbS is a semiconductor with a gap value of 2.114 eV. 50% Mn substituted by Pb leads to a slight decrease this value such that we found 0.94 and 1.321 eV using GGA + U and TB-mBJ approximations respectively. The behavior of Pb0.5Mn0.5S is antiferromagnetic. The dielectric function, absorption, and reflectivity, refraction index and optical conductivity are described in detail. The optical parameters are characterized by a single peak. The Pb0.5Mn0.5S peak shifts towards visible energy. The Seebeck coefficient, figure of merit, the thermal and the electrical conductivity are analyzed. The magnetic moment of Mn is obtained. The value of Neel temperature is 58 K. The maximum of magnetic entropy changes and the specific heat are 4.75 J.kg(-1).K-1 and 136 J.mol(-1) K-1 at H = 4 T respectively. The maximum RCP found is 232 J.kg(-1) for H = 4 T.

Automated summary

In this work, the structural, electronic, magneto-optic, magnetocaloric and thermoelectric properties of Mn-doped PbS were investigated using first-principles density functional calculations and Monte Carlo simulation. The results showed that Mn doping slightly decreased the band gap of PbS and Pb0.5Mn0.5S exhibited antiferromagnetic behavior. The optical and thermoelectric properties were also analyzed in detail.