Thermoelectric power in between two plateaus in quantum Hall effect

We have considered the response at two energies corresponding to two plateaus in the quantum Hall effect. Since the thermoelectric power involves the derivative of conductivity with respect to energy, we introduce the concept of a line width and hence an activation energy. We then use the Hall conductivity to define the thermoelectric power at the centre of two plateaus, which is found to vary monotonically as T^2 at low temperatures with fixed magnetic field. At elivated temperatures, the thermoelectric power varies as T(exp-\Delta/k_BT).