On the n-p phase transition in CdCr2-xSb xSe4

The electrical conductivity and the thermoelectric power measurements have been done in <0 0 1> direction and in the temperature range from 270 to 500 K for the single crystals with antimony concentration: 0.0 ≤ x ≤ 0.08. The electrical measurements showed that: (1) all single crystals are semiconductors, (2) all samples show typical Arrhenius behaviour of the electrical conductivity with two different energy activations, (3) the crystals with x = 0.06 and 0.08 revealed the n-p phase transitions at lower temperatures: 303 and 337 K, respectively, connected with a competition between the hole and electron conductivities. These effects are interpreted within a framework of the quantum band model including structural defects