Supersolid state in fermionic optical lattice systems

Masahisa Koga, Akihisa Koga

Masahisa Koga, Akihisa Koga

Akihisa Koga, Takuji Higashiyama, Kensuke Inaba +2 more

Huai-Bin Zhuang

Akihisa Koga, Takuji Higashiyama, Kensuke Inaba +2 more

We study ultracold fermionic atoms trapped in an optical lattice with harmonic confinement by means of the dynamical mean-field approximation. It is demonstrated that a supersolid state, where an s-wave superfluid coexists with a density-wave state with a checkerboard pattern, is stabilized by attractive onsite interactions on a square lattice. Our new finding here is that a confining potential plays an invaluable role in stabilizing the supersolid state. We establish a rich phase diagram at low temperatures, which clearly shows how the insulator, the density wave and the superfluid compete with each other to produce an intriguing domain structure. Our results shed light on the possibility of the supersolid state in fermionic optical lattice systems.

Akihisa Koga, Takuji Higashiyama, Kensuke Inaba +2 more

We study ultracold fermionic atoms loaded in an optical lattice with a confining potential. By combining dynamical mean-field approximation with a two-site impurity solver, we demonstrate that a supersolid state, where an s -wave superfluid coexists with a density-wave state of checkerboard pattern, is stabilized by attractive onsite interactions on a square lattice. The stability of the supersolid state in the thermodynamic limit is also addressed.