Refinement of the Two-Band Model Using Nonsaturating Magnetothermoelectric Coefficients in the Highly Compensated Semimetal NbSb₂

With growing interest in the magnetothermoelectric properties of semimetals, it becomes pertinent to develop and analyze methods for classifying and modeling their thermoelectric responses. We study the temperature and magnetic field dependence of the Seebeck and Nernst coefficients in the compensated semimetal NbSb₂.  At low temperatures and high fields, we find that the Seebeck coefficient increases quadratically and the Nernst coefficient increases linearly as a function of field without signs of saturation up to 14T.  We present a new analysis of magnetothermoelectricity in highly compensated semimetals, where the linear and quadratic field dependences of the Seebeck and Nernst signals impose stringent limitations on 2 band model fitting of the electrical conductivity, tightly constraining the carrier densities and mobilities [1,2].  We will discuss the implication of our results on the nonsaturating nature of the magnetoresistance and magnetothermoelectric effects.