Bandwidth-controlled Mott transition in κ−( BEDT−TTF)2Cu [N(CN)2]BrxCl1−x : Optical studies of localized charge excitations - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Physical Review B: Condensed Matter and Materials Physics (1998-2015) Année : 2007

Bandwidth-controlled Mott transition in κ−( BEDT−TTF)2Cu [N(CN)2]BrxCl1−x : Optical studies of localized charge excitations

Résumé

Infrared reflection measurements of the half-filled two-dimensional organic conductors kappa-(BEDT-TTF)2Cu[N(CN)2]BrxCl1−x (BEDT-TTF denotes bis-(ethylenedithio)tetrathiafulvalene] were performed as a function of temperature (5 K300 K) and Br substitution (x=0%, 40%, 73%, 85%, and 90%) in order to study the metal-insulator transition. We can distinguish absorption processes due to itinerant and localized charge carriers. The broad midinfrared absorption has two contributions: transitions between the two Hubbard bands and intradimer excitations from the charges localized on the (BEDT-TTF)2 dimer. Since the latter couple to intramolecular vibrations of BEDT-TTF, the analysis of both electronic and vibrational features provides a tool to disentangle these contributions and to follow their temperature and electronic-correlation dependence. Calculations based on the cluster model support our interpretation.

Dates et versions

hal-02541988 , version 1 (14-04-2020)

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Daniel Faltermeier, Jakob Barz, Michael Dumm, Martin Dressel, Natalia Drichko, et al.. Bandwidth-controlled Mott transition in κ−( BEDT−TTF)2Cu [N(CN)2]BrxCl1−x : Optical studies of localized charge excitations. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2007, 76 (16), pp.165113. ⟨10.1103/PhysRevB.76.165113⟩. ⟨hal-02541988⟩

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