Electronic, magnetic and transport properties of anti-ferromagnetic semiconductor BaGd2X4(X S, Se)

Thermoelectric materials, which are a functional ones that directly convert heat energy into electrical energy without any pollution, have attend widespread concentration. In the current paper, we have systematically investigated the stability, electronic, magnetic and transport properties of BaGd2X4 (XS, Se) compound. Stability is evaluated in terms of mechanics, dynamics and phase separation. Electronic calculations indicate that the BaGd2X4 (XS, Se) is an anti-ferromagnetic semiconductor with large band gap, and the origin of band gap is discussed by the hybridizations and distribution of electronic states. The magnetic moments of Gd atoms offer a main contribution to total one, and are discussed by the occupation of spin electrons in energy level. By using the Boltzmann transport theory along with Slack model, the thermoelectric properties of BaGd2X4 (XS, Se) were calculated. The zT values of p-type BaGd2S4 and BaGd2Se4 were found to be greater than 0.8 at 900 K. Particularly, the zT value of p-type BaGd2S4 reached 2.0, indicating its potential as an effective thermoelectric material.