Magnetic phases of spin-3/2 fermions on a spatially anisotropic square lattice

Article

关键词: NONLINEAR-SIGMA-MODEL;    CPN-1 MODEL;    QUANTUM ANTIFERROMAGNETS;    2 DIMENSIONS;    INSTANTONS;    EXPANSION;    THETA=PI;    DIAGRAM;    SYSTEMS;    PHYSICS;   

DOI  :  10.1103/PhysRevB.83.014418

来源: SCIE

【 摘 要 】

We study the magnetic phase diagram of spin-3/2 fermions in a spatially anisotropic square optical lattice at quarter filling (corresponding to one particle per lattice site). In the limit of the large on-site repulsion the system can be mapped to the so-called Sp(N) Heisenberg spin model with N = 4. We analyze the Sp(N) spin model with the help of the large-N field-theoretical approach and show that the effective theory corresponds to the Sp(N) extension of the CP(N-1) model, with the Lorentz invariance generically broken. We obtain the renormalization flow of the model couplings and show that although the Sp(N) terms are seemingly irrelevant, their presence leads to a renormalization of the CP(N-1) part of the action, driving a phase transition. We further consider the influence of the external magnetic field (the quadratic Zeeman effect) and present the qualitative analysis of the ground-state phase diagram.

【 授权许可】

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