Dispersive spectrum and orbital order of spinless p-band fermions in an optical lattice
- Institute of Theoretical and Computational Physics, Graz University of Technology, A-8010 Graz (Austria)
We study single-particle properties of a spinless p-band correlated fermionic gas in an optical lattice by means of a variational cluster approach (VCA). The single-particle spectral function is almost flat at half filling and develops a strongly dispersive behavior at lower fillings. The competition between different orbital orderings is studied as a function of filling. We observe that an 'antiferromagnetic' orbital order develops at half filling and is destroyed by doping the system evolving into a disordered orbital state. At low-filling limit, we discuss the possibility of 'ferromagnetic' orbital order by complementing the VCA result with observations based on a trial wave function. We also study the behavior of the momentum distribution for different values of the on-site interaction. Finally, we introduce an integration contour in the complex plane which allows to efficiently carry out Matsubara frequency sums.
- OSTI ID:
- 21287035
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 79, Issue 24; Other Information: DOI: 10.1103/PhysRevB.79.245109; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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