Electrical Properties of Tungsten-Ditelluride WTe₂

Abstract

The electrical resistivity, Hall coefficient and thermoelectric power of tungsten-ditelluride WTe₂ have been determined in the temperature range 4.2 to 600°K using single crystal specimens. The Hall coefficient is of n-type in the whole temperature range, while the thermoelectric power is of p-type below 60°K and of n-type above, with a maximum value at 350°K. The analysis of the Hall coefficient and thermoelectric power based on a three-carrier model leads to the following conclusions: (1) One band of electrons and two bands of holes (light and heavy) contribute to the transport phenomena. (2) At low temperatures heavy holes and electrons play dominant roles and at high temperatures the light holes take part in the conduction. (3) Heavy hole and electron bands overlap by 0.05 eV, and the energy gap between the electron band and light hole band is 0.075 eV.