High-frequency current oscillations in charge-density-wave 1T-TaS_2 devices: Revisiting the 'narrow band noise' concept

摘要

"We report on the current oscillations in quasi-2D 1T-TaS_2 charge-density-wave two-dimensional devices. The MHz-frequency range of the oscillations and the linear dependence of the frequency of the oscillations on the current closely resemble the narrow band noise, which was often observed in the classical bulk quasi-1D trichalcogenide charge-density-wave materials. In bulk quasi-1D materials, the narrow band noise was interpreted as direct evidence of charge-density-wave sliding. Despite the similarities, we argue that the nature of the MHz oscillations in 1T-TaS_2 is different from the narrow band noise. Analysis of the biasing conditions and current indicates that the observed oscillations are related to the current instabilities due to the voltage-induced transition from the nearly commensurate to incommensurate charge-density-wave phase.