Tracking TaS₂ CDW phases with cryo-STEM and in situ electric biasing

1T-TaS₂ is a 2D transition metal dichalcogenide which hosts several charge density wave (CDW) phases that can be accessed in different temperature ranges. Additionally, application of short electric pulses can trigger a metal-to-insulator transition (MIT) in TaS₂, which is promising for 2-terminal electronic devices. However, many questions remain unresolved in this system: what is the mechanism of the pulse-induced MIT (thermal or field-driven); how does the pulse-induced MIT couple to the CDW order parameters; and how do the transitions evolve spatiotemporally? In this talk I will discuss transmission electron microscopy (TEM) measurements of TaS₂ with cryogenic cooling and in situ electric biasing. Our TEM measurements include 4D-STEM mapping, atomic-resolution imaging, and time-resolved diffraction. This approach allows direct correlation of the CDW structures of TaS₂ with the electronic properties, both as a function of temperature and applied electric field.