TY - JOUR
T1 - Ultrafast photo-induced dynamics across the metal-insulator transition of VO2
AU - Wang, Siming
AU - Ramirez, Juan Gabriel
AU - Jeffet, Jonathan
AU - Bar-Ad, Shimshon
AU - Huppert, Dan
AU - Schuller, Ivan K.
N1 - Publisher Copyright:
© CopyrightEPLA, 2017.
PY - 2017/4
Y1 - 2017/4
N2 - The transient reflectivity of VO2 films across the metal-insulator transition clearly shows that with low-fluence excitation, when insulating domains are dominant, energy transfer from the optically excited electrons to the lattice is not instantaneous, but precedes the superheating-driven expansion of the metallic domains. This implies that the phase transition in the coexistence regime is lattice-, not electronically-driven, at weak laser excitation. The superheated phonons provide the latent heat required for the propagation of the optically-induced phase transition. For VO2 this transition path is significantly different from what has been reported in the strong-excitation regime. We also observe a slow-down of the superheating-driven expansion of the metallic domains around the metal-insulator transition, which is possibly due to the competition among several co-existing phases, or an emergent critical-like behavior.
AB - The transient reflectivity of VO2 films across the metal-insulator transition clearly shows that with low-fluence excitation, when insulating domains are dominant, energy transfer from the optically excited electrons to the lattice is not instantaneous, but precedes the superheating-driven expansion of the metallic domains. This implies that the phase transition in the coexistence regime is lattice-, not electronically-driven, at weak laser excitation. The superheated phonons provide the latent heat required for the propagation of the optically-induced phase transition. For VO2 this transition path is significantly different from what has been reported in the strong-excitation regime. We also observe a slow-down of the superheating-driven expansion of the metallic domains around the metal-insulator transition, which is possibly due to the competition among several co-existing phases, or an emergent critical-like behavior.
UR - http://www.scopus.com/inward/record.url?scp=85022012619&partnerID=8YFLogxK
U2 - 10.1209/0295-5075/118/27005
DO - 10.1209/0295-5075/118/27005
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AN - SCOPUS:85022012619
SN - 0295-5075
VL - 118
JO - Journal de Physique (Paris), Lettres
JF - Journal de Physique (Paris), Lettres
IS - 2
M1 - 27005
ER -