Akihisa Koga, Takamitsu Saitou, Atsushi Yamamoto
We study two-component fermions in optical lattices with spatially alternating on-site interactions by means of dynamical mean-field theory. Calculating a quasiparticle weight, double occupancy, and order parameters for each sublattice, we discuss low-temperature properties in the system. When the repulsive interactions alternate, the magnetically ordered state is realized at half filling, while the superfluid state is realized in the attractive case. Furthermore, we find that the metal-insulator transition occurs against magnetic and superfluid fluctuations when the repulsive and attractive interactions alternate. In the doped system, the commensurability emerges due to the repulsive interactions and the insulating state is realized down to the quarter-filling.
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http://arxiv.org/abs/1207.2150
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