Boron isotope effects on the thermoelectric properties of UB 4 at low temperatures

Abstract

The thermoelectric power and electrical resistivity of UB 4 with three different boron isotope enrichments were measured in the temperature range from 80 to 300 K. The thermoelectric power of each sample decreased with decreasing temperature, but a slight saturation of the decrease due to phonon-drag effect was observed below 120 K for both boron isotope enriched samples. The resistivity decreased with decreasing temperature and there existed no large difference among the resistivities of natural boron, boron-10 enriched and boron-11 enriched samples. The figure of merit for thermoelectricity of UB 4 was lower by three orders of magnitude than that of well-known thermoelectric material (Bi,Sb) 2(Te,Se) 3.