Enhanced thermopower and low thermal conductivity in p-type polycrystalline ZrTe5

Thermoelectric properties of polycrystalline p-type ZrTe5 are reported in temperature (T) range 2 - 340 K. Thermoelectric power (S) is positive and reaches up to 458 uV/K at 340 K on increasing T. The value of Fermi energy 16 meV, suggests low carrier density of ~ 9.5 X 10^18 cm-3. A sharp anomaly in S data is observed at 38 K, which seems intrinsic to p-type ZrTe5. The thermal conductivity value is low (2 W/m-K at T = 300 K) with major contribution from lattice part. Electrical resistivity data shows metal to semiconductor transition at T ~ 150 K and non-Arrhenius behavior in the semiconducting region. The figure of merit zT (0.026 at T = 300 K) is ~ 63% higher than HfTe5 (0.016), and better than the conventional SnTe, p-type PbTe and bipolar pristine ZrTe5 compounds.