Proximity of the layered organic conductors {alpha}-(BEDT-TTF){sub 2}MHg(SCN){sub4} (M=K, NH{sub 4}) to a charge-ordering transtion.

Journal Article · Fri Apr 25 04:00:00 EDT 2003 · Phys. Rev. Lett.

DOI:https://doi.org/10.1103/PhysRevLett.90.167002· OSTI ID:949716

Dressel, M; Drichko, N; Schlueter, J; Merino, J

While the optical properties of the superconducting salt {alpha}-(BEDT-TTF){sub 2}-NH{sub 4}Hg(SCN){sub 4} remain metallic down to 2 K, in the nonsuperconducting K analog a pseudogap develops at frequencies of about 200 cm-1 for temperatures T<200 K. We show that the optical conductivity calculated with exact-diagonalization techniques on an extended Hubbard model at quarter filling is consistent with the observed low-frequency feature. We argue that the different optical responses observed are a consequence of the proximity of these compounds to a charge-ordering transition driven by the intermolecular Coulomb repulsion.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; FOR
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 949716
• Report Number(s): ANL/MSD/JA-43632
• Journal Information: Phys. Rev. Lett., Journal Name: Phys. Rev. Lett. Journal Issue: Apr. 25, 2003 Vol. 90; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
BEDT-TTF
COULOMB FIELD
HUBBARD MODEL
OPTICAL PROPERTIES