TY - JOUR
T1 - Ultrafast IR and THz spectroscopy of photo-induced insulator to metal transition in highly correlated organic system
AU - Iwai, Shinichiro
N1 - Funding Information:
We thank our collaborators K. Yamamoto, K. Yakushi, T. Sasaki, N. Yoneyama, N. Kobayashi, S. Saito, Y. Takahashi, Y. Kawakami, H. Nakaya, K. Itoh, A. Kashiwazaki, F. Hiramatsu. We also thank K. Yonemitsu, K. Iwano, S. Ishihara, H. Matsueda, A. Takahashi, H. Seo, H. Kishida, H. Sawa, M. Watanabe, R. Kondou and Y. Nishio for their helpful discussions. This work was supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology “New frontier in materials science opened by molecular degrees of freedom” (No. 20110005 ) and B, No. 20340069 .
PY - 2011/3
Y1 - 2011/3
N2 - Photo-induced insulator to metal transitions (PIMT) in quarter filled layered organic conductors ET [bis(ethylenedithio)tetrathiafulvalene]-based salts α-(ET)2I3, θ-(ET)2RbZn(SCN) 4, and κ-(d-ET)2Cu[N(CN)2Br] were investigated using ultrafast spectroscopy in the near, mid-infrared and terahertz (THz) regions. In charge ordered salts α-(ET)2I 3 and θ-(ET)2RbZn(SCN)4, an immediate (<30 fs) generation of a microscopic metallic state is driven by the electronic process. Subsequently, condensation of the microscopic metallic domain to the macroscopic scale is accompanied by a small molecular rearrangement in α-(ET)2I3. However, in θ-(ET)2RbZn(SCN)4, a large structural difference between the insulator and metallic phases prevents stabilization of the macroscopic metallic state. In a dimer Mott insulator κ-(d-ET) 2Cu[N(CN)2Br], photo-generation of the metallic state shows a finite rise time of ca. 1 ps, which is attributable to the photo-induced change of on-site Coulomb energy on each dimer (Udim) through dimeric molecular rearrangement. Thus, the ultrafast dynamics of PIMT depend strongly on the molecular arrangement in the layer of ET salts.
AB - Photo-induced insulator to metal transitions (PIMT) in quarter filled layered organic conductors ET [bis(ethylenedithio)tetrathiafulvalene]-based salts α-(ET)2I3, θ-(ET)2RbZn(SCN) 4, and κ-(d-ET)2Cu[N(CN)2Br] were investigated using ultrafast spectroscopy in the near, mid-infrared and terahertz (THz) regions. In charge ordered salts α-(ET)2I 3 and θ-(ET)2RbZn(SCN)4, an immediate (<30 fs) generation of a microscopic metallic state is driven by the electronic process. Subsequently, condensation of the microscopic metallic domain to the macroscopic scale is accompanied by a small molecular rearrangement in α-(ET)2I3. However, in θ-(ET)2RbZn(SCN)4, a large structural difference between the insulator and metallic phases prevents stabilization of the macroscopic metallic state. In a dimer Mott insulator κ-(d-ET) 2Cu[N(CN)2Br], photo-generation of the metallic state shows a finite rise time of ca. 1 ps, which is attributable to the photo-induced change of on-site Coulomb energy on each dimer (Udim) through dimeric molecular rearrangement. Thus, the ultrafast dynamics of PIMT depend strongly on the molecular arrangement in the layer of ET salts.
KW - Charge order
KW - Correlated electron system
KW - Mott insulator
KW - Organic conductor
KW - Photo-induced phase transition
KW - Ultarfast spectroscopy
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U2 - 10.1016/j.jlumin.2010.12.014
DO - 10.1016/j.jlumin.2010.12.014
M3 - Article
AN - SCOPUS:79952189164
VL - 131
SP - 409
EP - 414
JO - Journal of Luminescence
JF - Journal of Luminescence
SN - 0022-2313
IS - 3
ER -