The effect of charged additives on the conductivity and the thermopower in liquid selenium

The simultaneous measurements of conductivoty σ and thermopower S for liquid Se and its dilute mixtures containing Na, Tl and Cl have been performed in the temperature and pressure range up to 1500°C and 2200 bar. The addition of Na, Tl and Cl give rise to a substantial increase in σ at low temperatures. The value of S of liquid Se is large positive at low temperature. The sign of S is changed to be negative by addition of Na and Tl. By the addition of Cl the sign of S remains positive and the value increases. The effect of charged additives on the transport properties of liquid Se is discussed in connection with the change of the bonding configuration.