Ultrafast triggering of insulator-metal transition in two-dimensional VSe2

Deepnarayan Biswas, Alfred Jones, Paulina Ewa Majchrzak, Byoung Ki Choi, Tsung Han Lee, Klara Volckaert, jiagui feng, Igor Markovic, Federico Andreatta, Chang-Jong Kang, hyuk jin kim, In Hak Lee, Chris Joswiak, Eli Rotenberg, Aaron Bostwick, Charlotte Sanders, Yu Zhang, Gabriel Karras, Richard T. Chapman, Adam S WyattEmma Springgate, Jill Miwa, Philip Hofmann, Phil D.C. King, Young Jun Chang, Nicola Lanata, Søren Ulstrup*

*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review


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.

TidsskriftNano Letters
Sider (fra-til)1968-1975
Antal sider8
StatusUdgivet - mar. 2021


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