First-principles calculation of electronic density of states and Seebeck coefficient in transition-metal-doped Si–Ge alloys

Abstract

High ZT value and large Seebeck coefficient have been reported in the nanostructured Fe-doped Si–Ge alloys. In this work, the large Seebeck coefficient in Fe-doped Si–Ge systems was qualitatively reproduced from the computed electronic density of states, where a hybrid functional, HSE06, was used for an exchange-correlation functional, as well as a special quasi-random structure (SQS) for a disordered atomic configuration. Furthermore, by replacing Fe with other transition metals, such as Mn, Co, Ni, Cu, Zn, and Au, a dopant that produces a large Seebeck coefficient in Si–Ge alloy systems was explored. It was found that the Mn-doped system produces a large Seebeck coefficient comparable with the Fe-doped system.