Chang, SY and Pathak, S and Trivedi, N (2012) Repulsive fermions in optical lattices: Phase separation versus coexistence of antiferromagnetism and d-wave superfluidity. In: Physical Review A, 85 (1). 013625-1-013625-9.
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We investigate a system of fermions on a two-dimensional optical square lattice in the strongly repulsive coupling regime. In this case, the interactions can be controlled by laser intensity as well as by Feshbach resonance. We compare the energetics of states with resonating valence bond d-wave superfluidity, antiferromagnetic long-range order, and a homogeneous state with coexistence of superfluidity and antiferromagnetism. Using a variational formalism, we show that the energy density of a hole e(hole)(x) has a minimum at doping x = x(c) that signals phase separation between the antiferromagnetic and d-wave paired superfluid phases. The energy of the phase-separated ground state is, however, found to be very close to that of a homogeneous state with coexisting antiferromagnetic and superfluid orders. We explore the dependence of the energy on the interaction strength and on the three-site hopping terms and compare with the nearest-neighbor hopping t-J model.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to American Physical Society.|
|Department/Centre:||Division of Chemical Sciences > Materials Research Centre|
|Date Deposited:||15 Feb 2012 04:42|
|Last Modified:||15 Feb 2012 04:42|
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