Thermoelectric properties of Mg3Sb2-xBix single crystals grown by Bridgman method

초록

We studied the low-temperature thermoelectric properties of single crystals of Mg3Sb2-xBix (0 <= x <= 2) grown by the Bridgman method. The crystals are well aligned along the hexagonal c axis as documented in the huge anisotropy of the electrical resistivity; rho(//c)/rho(perpendicular to c) = 100 for x = 2. Upon increasing x, the semiconducting behaviour in rho(T) changes to the metallic behaviour, and the Seebeck coefficient S(T) at room temperature decreases from 590 mu V K-1 for x = 0 to 67 mu V K-1 for x= 2. Although the thermal conductivity at 300 K is as low as 0.88 W mK(-1) for x = 0.7, the large resistivity of 1 Omega cm leaves the figure of merit, ZT, at a low level of 5.8 x 10(-3) at 300 K.

키워드