Title
Charge order and metal-insulator transition in the chiral molecular conductors (DM-EDT-TTF)2X(X = ClO4, ReO4)
Authors
[ 1 ] Instytut Badań Materiałowych i Inżynierii Kwantowej, Wydział Inżynierii Materiałowej i Fizyki Technicznej, Politechnika Poznańska | [ P ] employee
Scientific discipline (Law 2.0)
Year of publication
2025
Published in
Article type
scientific article
Publication language
english
Keywords
EN
- chiral molecular conductors
- metal-insulator transition
- charge order
- optical spectroscopy
Abstract
EN 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 105 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.
Pages (from - to)
085125-1 - 085125-11
Ministry points / journal
140
System created by Poznań University of Technology
and Poznan Supercomputing and Networking Center
Log in through eKonto to add to SIS