Article Dans Une Revue (Article De Synthèse) Physical Review B Année : 2025

Charge order and metal-insulator transition in chiral molecular conductors (DM-EDT-TTF) 2 X, (X=ClO 4 , ReO 4 )

M. Sawińska
A. Frąckowiak
I. Olejniczak
T. Runka
F. Pop
N. Avarvari

Résumé

Optical measurements reveal the charge-ordered nature of the insulating state in the chiral molecular conductors [(S,S/R,R)-DM-EDT-TTF]2ClO4 (DM-Cl) and [(S,S/R,R)-DM-EDT-TTF]2ReO4 (DM-Re). These enantiopure materials exhibit metallic conductivity at room temperature and a metal-insulator transition upon cooling below TMI = 40 and 120 K, respectively. Optical conductivity spectra display a polarization-independent in-plane response, attributed to the hexagonal structure of the conducting DM-EDT-TTF layer, featuring broadband electronic excitations, molecular vibrational modes, and a Drude component in the metallic phase. The gap opening at 150 and 250 cm -1 for DM-Cl and DM-Re, respectively, signals the transition from a metallic to an insulating state upon cooling. Drude-Lorentz-Fano analysis of the optical spectra yields Hubbard parameters, the intersite Coulomb repulsion V and the bandwidth W, supporting the presence of charge order in the insulating phase. Raman spectra of DM-Cl and DM-Re, focusing on charge-sensitive molecular vibrations, further confirm a charge-ordered insulating state with a charge disproportionation of 0.10e and 0.13e, respectively. Strong DM-EDT-TTF molecular modes, activated in optical spectra through coupling with the electronic background, support the presence of lattice frustration.

Fichier principal
Vignette du fichier
I.Olejniczak_BD14960_revised_highlighted.pdf (1.36 Mo) Télécharger le fichier
Origine Fichiers produits par l'(les) auteur(s)
Licence

Dates et versions

hal-05395501 , version 1 (03-12-2025)

Licence

Identifiants

Citer

M. Sawińska, A. Frąckowiak, I. Olejniczak, T. Runka, S. Priya, et al.. Charge order and metal-insulator transition in chiral molecular conductors (DM-EDT-TTF) 2 X, (X=ClO 4 , ReO 4 ). Physical Review B, 2025, 112 (8), pp.085125. ⟨10.1103/jb8y-vs48⟩. ⟨hal-05395501⟩
23 Consultations
115 Téléchargements

Altmetric

Partager

  • More