Real-Time Observation of Slowed Charge Density Wave Dynamics in Thinned 1T-TaS2

Abstract

Transient electrical pulsing is used to investigate the slowed charge density wave (CDW) kinetics of 1T-TaS₂. These measurements distinguish a fast response of the material, consistent with the onset of self-heating, from much slower transients that occur on timescales orders of magnitude longer than this. The latter variations appear consistent with slow configurational changes in the CDW, which, due to the thin nature of the 1T-TaS₂, can be distinguished from the much faster dynamics of Joule heating. Experiments in which the cooling of the material is interrupted, demonstrate the possibility of “programming” it in different, strongly nonequilibrium, CDW phases. Collectively, the results point to the existence of a complex free-energy space for the thinned material, whose multi-valley structure and hidden metastable states govern the resulting thermal and field-driven dynamics. Crucially, this work demonstrates that while the CDW dynamics in this material may have a thermal character, the timescales associated with these motions can be very different from those on which self-heating occurs. This discovery will be important for efforts to implement active devices that utilize the CDW states of thinned 1T-TaS₂.