Competing Pairing Symmetries in a Generalized Two-Orbital Model for the Pnictide Superconductors

Journal Article · Sat Jan 01 00:00:00 EST 2011 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.106.217002· OSTI ID:1018643

Nicholson, Andrew D ^[1]; Ge, Weihao ^[2]; Zhang, Xiaotian ^[3]; Riera, J. A. ^[4]; Daghofer, M. ^[5]; Olés, Andrzej M. ^[6]; Martins, G. B. ^[7]; Moreo, Adriana ^[1]; Dagotto, Elbio R ^[1]

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1. ORNL
2. University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)
3. Oak Ridge National Laboratory (ORNL)
4. Universidad Nacional de Rosario
5. IFW Dresden
6. Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany
7. Oakland University, Rochester, MI

We introduce and study an extended t-U-J two-orbital model for the pnictides that includes Heisenberg terms deduced from the strong coupling expansion. Including these J terms explicitly allows us to enhance the strength of the %;0 - 0;% spin order which favors the presence of tightly bound pairing states even in the small clusters that are here exactly diagonalized. The A1g and B2g pairing symmetries are found to compete in the realistic spin-ordered and metallic regime. The dynamical pairing susceptibility additionally unveils low-lying B1g states, suggesting that small changes in parameters may render any of the three channels stable.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1018643
• Journal Information: Physical Review Letters, Vol. 106, Issue 21; ISSN 0031--9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
PNICTIDES
SPIN
SUPERCONDUCTORS