Login / Signup

Ultrafast Triggering of Insulator-Metal Transition in Two-Dimensional VSe2.

Deepnarayan BiswasAlfred J H JonesPaulina MajchrzakByoung Ki ChoiTsung-Han LeeKlara VolckaertJiagui FengIgor MarkovićFederico AndreattaChang-Jong KangHyuk Jin KimIn Hak LeeChristopher JozwiakEli RotenbergAaron BostwickCharlotte E SandersYu ZhangGabriel KarrasRichard T ChapmanAdam S WyattEmma SpringateJill A MiwaPhilip HofmannPhil D C KingYoung Jun ChangNicola LanatàSøren Ulstrup
Published in: Nano letters (2021)
The transition-metal dichalcogenide VSe2 exhibits an increased charge density wave transition temperature and an emerging insulating phase when thinned to a single layer. Here, we investigate the interplay of electronic and lattice degrees of freedom that underpin these phases in single-layer VSe2 using ultrafast pump-probe photoemission spectroscopy. In the insulating state, we observe a light-induced closure of the energy gap, which we disentangle from the ensuing hot carrier dynamics by fitting a model spectral function to the time-dependent photoemission intensity. This procedure leads to an estimated time scale of 480 fs for the closure of the gap, which suggests that the phase transition in single-layer VSe2 is driven by electron-lattice interactions rather than by Mott-like electronic effects. The ultrafast optical switching of these interactions in SL VSe2 demonstrates the potential for controlling phase transitions in 2D materials with light.
Keyphrases
  • transition metal
  • energy transfer
  • high resolution
  • electron transfer
  • quantum dots
  • minimally invasive
  • computed tomography
  • single molecule
  • magnetic resonance
  • risk assessment
  • climate change