I-U characteristics measured in ${\mathrm{TlGaTe}}_2$ single crystals consist of two regimes: a linear one at low current densities and a nonlinear one at higher current densities. In the nonlinear part [negative-differential-resistance (NDR) region] of the curves, a considerable increase of the temperature of the sample was registered. Additionally, voltage oscillations were observed in this region. Arrhenius plots (lnσ vs ${10}^3$/${\mathit{T}}_0$ plots) recorded in the Ohmic part of the I-U curves show a temperature dependence of the conductivity. This fact, in combination with a purely thermal mechanism, can well explain both the formation of the NDR region and the temperature elevation in this region.

• Received 9 October 1992

DOI:https://doi.org/10.1103/PhysRevB.47.4261