Theoretical search for p-type dopants in Mg_2X (X= Si, Ge) semiconductors for thermoelectricity

摘要

Electronic structure calculations of doped Mg_2(Si-Ge) semiconductors were performed by the charge self-consistent Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) in order to search for p-type impurities. It was predicted that Li and Na (located on Mg site) as well as B, Ru, Mo and W (located on Si site) are expected to behave as hole donors in Mg_2(Si-Ge). Using the calculated density of states in doped Mg_2Si in the vicinity of the Fermi level, the linear term of thermopower was also estimated from the simplified Mott's formula. The RT Seebeck coefficient may range from 120μV/K (Li) to almost 300μV/K (Ru) at the 1% content of doped impurities.