Anisotropy and high thermopower of LaOBiS2

•The high anisotropy of the thermoelectric coefficient.•Comparison of theory and experiment.•DFT calculations of electronic properties.

Transport properties of LaOBiS2 are studied using the Boltzmann theory in the constant scattering time approximation, the input to which are derived from the ab-initio calculations with spin–orbit interactions included. By virtue of the materials chemical bonding and band structure, strong anisotropy in the transport is observed, which also have non-symmetric behavior with respect to carrier type. With thermopower being in few hundreds μV/K, and LaO layers being charge inactive, it could be well anticipated that the thermal conductivity would be significantly suppressed along the crystallographic c-axis. We argue LaOBiS2 as a potential oxide thermoelectric material for high temperature applications. Further optimization of the materials properties in terms of “p” and “n” type conduction could also be accomplished via Sr and F doping, respectively, following the discovery of its isoelectronic counterpart SrFBiS2.