Evidence for a thermally driven charge-density-wave transition in 1T-TaS2 thin-film devices: Prospects for GHz switching speed

We report on the room-temperature switching of 1T-TaS2 thin-film charge-density-wave devices, using nanosecond-duration electrical pulsing to construct their time-resolved current-voltage characteristics. The switching action is based upon the nearly commensurate to incommensurate charge-density-wave phase transition in this material, which has a characteristic temperature of 350K at thermal equilibrium. For sufficiently short pulses, with rise times in the nanosecond range, self-heating of the devices is suppressed, and their current-voltage characteristics are weakly nonlinear and free of hysteresis. This changes as the pulse duration is increased to similar to 200ns, where the current develops pronounced hysteresis that evolves nonmonotonically with the pulse duration. By combining the results of our experiments with a numerical analysis of transient heat diffusion in these devices, we clearly reveal the thermal origins of their switching. In spite of this thermal character, our modeling suggests that suitable reduction of the size of these devices should allow their operation at GHz frequencies.

Automated summary

This study reports the room-temperature switching of 1T-TaS2 thin-film charge-density-wave devices using nanosecond-duration electrical pulsing to construct their time-resolved current-voltage characteristics. The switching action is based on the charge-density-wave phase transition in the material, and self-heating of the devices is suppressed for short pulses, causing weakly non-linear current-voltage characteristics. As the pulse duration increases, hysteresis in the current develops nonmonotonically.