Suppression of the resistivity anomaly and corresponding thermopower behavior in the pentatelluride system by the addition of Sb : Hf1-XZrXTe5-YSbY -art. no. 121104

The electrical resistivity rho and the thermopower alpha of the transition- metal pentatelluride system Hf1-xZrxTe5-YSbY have been measured over a broa d range of temperature, 10 K< T< 300 K. The systematic Sb doping of these m aterials has been performed over a range from 0<Y<0.75, where Y is the nomi nal Sb concentration. Both parent materials (HfTe5 and ZrTe5) exhibit an an omalous resistive peak, T-P approximate to 80 K for HfTe5 and T-P approxima te to 145 K for ZrTe5. Each parent material displays a large positive (p-ty pe) thermopower (alpha greater than or equal to + 125 muV/K) around room te mperature, which undergoes a change to a large negative (n-type) thermopowe r (alpha less than or equal to - 125 muV/K) below the peak temperature. At a specific level of Sb doping the resistive anomaly is no longer evident an d results in a semimetallic temperature dependence. In addition the thermop ower monotonically decreases with temperature with no change in sign as in the parent materials. X-ray-diffraction data reveals that the pentatellurid e structure is still preserved at all doping concentrations.