Electrical transport in new Tl₂OCl₂ and Tl₄Cl₆

Abstract

Electrical conductivity, σ, Seebeck coefficient, S, measurements on the pressed solid pellets of both Tl₂OCl₂ and Tl₄Cl₆ have been carried out in the temperature range 300 to 580 K. Both log a and S against T ⁻¹ plots have two linear regions with a break at temperature T _B and T′ _B for both solids. T′ _B has been found to few degrees less than T _B, which has been shown due to the experimental condition employed in the measurement of σ and S. These solids are electronic conductors with relatively high conductivity. The conduction above T _B, results due to thermal excitation of electrons from valence to conduction band. The energy band gap for Tl₂OCl₂ and Tl₄Cl₆ have been found to be 1.38 and 1.68 eV, respectively. Below T _B, the hopping of electrons from Tl⁺¹ to Tl⁺³ becomes the dominant conduction mechanism. The estimated values of mobility in this range for both the solids are of the order of 10⁻⁶ m² V ⁻¹sec⁻¹.