Premium
Optical investigations of the superconducting energy gap in β″‐(BEDT‐TTF) 2 SF 5 CH 2 CF 2 SO 3
Author(s) -
Kaiser S.,
Yasin S.,
Drichko N.,
Dressel M.,
Rõõm T.,
Hüvonen D.,
Nagel U.,
Gard G. L.,
Schlueter J. A.
Publication year - 2012
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201100526
Subject(s) - superconductivity , condensed matter physics , physics , optical conductivity , order (exchange) , charge (physics) , band gap , electrical resistivity and conductivity , metal , energy (signal processing) , conductivity , chemistry , quantum mechanics , organic chemistry , finance , economics
The organic salt β″‐(BEDT‐TTF) 2 SF 5 CH 2 CF 2 SO 3 is a two‐dimensional metal with a quarter‐filled conduction band. In the metallic state the optical conductivity evidences interaction of the charge carriers with charge‐order fluctuations that become stronger as temperature decreases. In the superconducting phase below T c ≈ 5 K, indications of the superconducting gap with $2{\rm \Delta }\approx 12\;{\rm cm}^{- 1} $ are observed in the optical spectrum, corresponding to $2{\rm \Delta }/k_{{\rm B}} T_{{\rm c}} \approx 3.3$ . Its temperature and magnetic field dependences are also consistent with predictions by the BCS theory of a weakly coupled superconductor.The conductivity ratio $\sigma _{1} (T = 1.75\;{\rm K})/\sigma _{1} (10\;{\rm K})$ indicates the opening of the superconducting gap in β″‐(BEDT‐TTF) 2 SF 5 CH 2 CF 2 SO 3 .