Pairing symmetries of a hole-doped extended two-orbital model for the pnictides

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.85.024532· OSTI ID:1039645

Nicholson, Andrew D ^[1]; Ge, Weihao ^[2]; Riera, J. A. ^[3]; Daghofer, Maria ^[1]; 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. Universidad Nacional de Rosario

The hole-doped ground state of a recently introduced extended t-U-J two-orbital Hubbard model for the Fe-based superconductors is studied via exact diagonalization methods on small clusters. Similarly as in the previously studied case of electron doping [A. Nicholson et al., Phys. Rev. Lett. 106, 217002 (2011)], upon hole doping it is observed that there are several competing pairing symmetries, including A1g , B1g , and B2g . However, contrary to the electron-doped case, the ground state of the hole-doped state has pseudocrystal momentum k = ( , ) in the unfolded Brillouin zone. In the two Fe-atom per unit cell representation, this indicates that the ground state involves antibonding, rather than bonding, combinations of the orbitals of the two Fe atoms in the unit cell. The lowest state with k = (0,0) has only a slightly higher energy. These results indicate that this simple two-orbital model may be useful to capture some subtle aspects of the hole-doped pnictides, since calculations for the five-orbital model have unveiled a hole pocket centered at M [k = ( , )] in the unfolded Brillouin zone.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1039645
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 2 Vol. 85; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ATOMS
BONDING
BRILLOUIN ZONES
ELECTRONS
GROUND STATES
HUBBARD MODEL
PNICTIDES
SUPERCONDUCTORS