We report on the first experiments with atomic Fermi gases in optical lattices. We have studied the properties of non interacting fermions and of an interacting boson‐fermion mixture in a 1D lattice in presence of additional linear or harmonic potentials. These systems have allowed to study for the first time the fundamental quantum transport properties of a perfect crystal and to confirm the role of interactions in real crystals. We have found that the combination of Fermi gases and optical lattices can also have important applications, such as high‐resolution force sensing.We report on the first experiments with atomic Fermi gases in optical lattices. We have studied the properties of non interacting fermions and of an interacting boson‐fermion mixture in a 1D lattice in presence of additional linear or harmonic potentials. These systems have allowed to study for the first time the fundamental quantum transport properties of a perfect crystal and to confirm the role of interactions in real crystals. We have found that the combination of Fermi gases and optical lattices can also have important applications, such as high‐resolution force sensing.

AIP conference proceedingsJan 1, 20052 citations

Stripe, checkerboard, and liquid-crystal ordering from anisotropic p -orbital Fermi surfaces in optical lattices

Zixu Zhang, Xiaopeng Li, W. Vincent Liu

We study instabilities of single-species fermionic atoms in the $p$ -orbital bands in two-dimensional optical lattices at noninteger filling against interactions. Charge density wave and orbital density wave orders with stripe or checkerboard patterns are found for attractive and repulsive interactions, respectively. The superfluid phase, usually expected of attractively interacting fermions, is strongly suppressed. We also use field theory to analyze the possible phase transitions from orbital stripe order to liquid-crystal phases and obtain the phase diagram. The condition of nearly-perfect Fermi-surface nesting, which is key to the above results, is shown robustly independent of fermion fillings in such $p$ -orbital systems, and the $(2{k}_{F},\ifmmode\pm\else\textpm\fi{}2{k}_{F})$ momentum of density wave oscillation is highly tunable. Such remarkable features show the promise of making those exotic orbital phases, which are of broad interest in condensed-matter physics, experimentally realizable with optical lattice gases.We study instabilities of single-species fermionic atoms in the $p$-orbital bands in two-dimensional optical lattices at noninteger filling against interactions. Charge density wave and orbital density wave orders with stripe or checkerboard patterns are found for attractive and repulsive interactions, respectively. The superfluid phase, usually expected of attractively interacting fermions, is strongly suppressed. We also use field theory to analyze the possible phase transitions from orbital stripe order to liquid-crystal phases and obtain the phase diagram. The condition of nearly-perfect Fermi-surface nesting, which is key to the above results, is shown robustly independent of fermion fillings in such $p$-orbital systems, and the $(2{k}_{F},\ifmmode\pm\else\textpm\fi{}2{k}_{F})$ momentum of density wave oscillation is highly tunable. Such remarkable features show the promise of making those exotic orbital phases, which are of broad interest in condensed-matter physics, experimentally realizable with optical lattice gases.

arXiv:1105.3387Physical Review AMay 8, 20129 citations

We study instabilities of single-species fermionic atoms in the

p

-orbital bands in two-dimensional optical lattices at noninteger filling against interactions. Charge density wave and orbital density wave orders with stripe or checkerboard patterns are found for attractive and repulsive interactions, respectively. The superfluid phase, usually expected of attractively interacting fermions, is strongly suppressed. We also use field theory to analyze the possible phase transitions from orbital stripe order to liquid-crystal phases and obtain the phase diagram. The condition of nearly-perfect Fermi-surface nesting, which is key to the above results, is shown robustly independent of fermion fillings in such

p

-orbital systems, and the $(2{k}_{F},\ifmmode\pm\else\textpm\fi{}2{k}_{F})$ momentum of density wave oscillation is highly tunable. Such remarkable features show the promise of making those exotic orbital phases, which are of broad interest in condensed-matter physics, experimentally realizable with optical lattice gases.