High anisotropy in the electronic and thermoelectric properties of layered oxysulfides: A case study of LaOPbBiS₃

In this paper, we investigate the atomic and electronic structure and the lattice dynamics of layered oxysulfide LaOPbBiS₃ using first-principles Density Functional Theory (DFT) and Density Functional Perturbation Theory (DFPT) calculations. The thermoelectric (TE) properties are characterized by semi-classical Boltzmann theory with rigid band approximation. We find high anisotropy in the electronic structure due to a tetragonal crystal structure of the material and weaker electronic interaction between the interlayer. Strong hybridization of acoustic phonon modes and low-frequency optical mode is observed in our simulation.