Volume 88, Number 3, November 2009
Article Number 36001
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 02 November 2009
EPL, 88 (2009) 36001
DOI: 10.1209/0295-5075/88/36001

Strongly interacting two-dimensional Dirac fermions

L.-K. Lim1, A. Lazarides1, A. Hemmerich2 and C. Morais Smith1

1   Institute for Theoretical Physics, Utrecht University - Leuvenlaan 4, 3584 CE Utrecht, The Netherlands, EU
2   Institut für Laser-Physik, Universität Hamburg - Luruper Chaussee 149, 22761 Hamburg, Germany, EU

received on 23 September 2009; accepted in final form by M. Lewenstein on 14 October 2009; published November 2009
published online 2 November 2009

We show how strongly interacting two-dimensional Dirac fermions can be realized with ultracold atoms in a two-dimensional optical square lattice with an experimentally realistic, inherent gauge field, which breaks time reversal and inversion symmetries. We find remarkable phenomena in a temperature range around a tenth of the Fermi temperature, accessible with present experimental techniques: at zero chemical potential, besides a conventional s-wave superconducting phase, unconventional superconductivity with non-local bond pairing arises. In a temperature vs. doping phase diagram, the unconventional superconducting phase exhibits a dome structure, reminiscent of the phase diagram for high-temperature superconductors and heavy fermions.

67.85.Pq - Mixtures of Bose and Fermi gases.
37.10.Jk - Atoms in optical lattices.
71.10.Fd - Lattice fermion models (Hubbard model, etc.).

© EPLA 2009