Anomalous Magneto-thermal Transport Properties of three-dimensional Dirac Semi-metal Cd$_{3}$As$_{2}$

Thermoelectric power of Dirac semimetal Cd$_{3}$As$_{2}$ exhibits linear temperature dependence, which is in agreement with the semiclassical Mott's relation. Linear energy dispersion of three-dimensional Dirac fermion is clearly reflected in high field saturation of thermoelectric power. The scattering time crosses over from nearly energy independent to linear energy dependent with increasing magnetic field. Thermal conductivity decreases rapidly with magnetic field and, similar to thermoelectric power, it saturates at high fields. Unlike Fermi liquid systems, the enhancement in electrical to thermal conductivity ratio and thermoelectric power with magnetic field results a large magneto-thermoelectric figure of merit above room temperature.