Charge ordering and superconductivity in {alpha}-(BEDT-TTF){sub 2}MHg(SCN){sub 4}.

Journal Article · Fri Nov 01 04:00:00 EST 2002 · J. Phys. IV France

OSTI ID:961237

Dressel, M; Drichko, N; Salameh, B; Thoms, J; Schlueter, J; Merino, J

In the optical spectra of the non-superconducting salt {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4}4 a strong feature appears at frequencies of about 200 cm{sup -1} and temperatures below 200 K which indicates the opening of a pseudogap. This is in contrast to the superconducting {alpha}-(BEDT-TTF){sub 2}NH{sub 4}Hg(SCN){sub 4} which exhibits metallic-like optical properties down to 2 K. Based on exact diagonalisation calculations of the optical conductivity on an extended Hubbard model at quarter-filling we argue that the proximity of these salts to a charge ordering transition is responsible for the observed pseudogap. Our proposed scenario suggests that the different ground states, including superconductivity, are a consequence of the fluctuations associated with short range charge ordering which builds up close to the quantum phase transition.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; FOR
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 961237
• Report Number(s): ANL/MSD/JA-45657
• Journal Information: J. Phys. IV France, Journal Name: J. Phys. IV France Journal Issue: PR9 ; Nov. 2002 Vol. 12
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
BEDT-TTF
FLUCTUATIONS
GROUND STATES
HUBBARD MODEL
OPTICAL PROPERTIES
RANGE
SALTS
SPECTRA
SUPERCONDUCTIVITY
TEMPERATURE RANGE 0065-0273 K