Transition from band insulator to Mott insulator and formation of local moment in the half-filled ionic SU(N) Hubbard model

Article

关键词: LARGE-N LIMIT;    WAVE-FUNCTIONS;    GROUND-STATES;    SPIN-PEIERLS;    VALENCE-BOND;    QUANTUM;    GUTZWILLER;    FIELD;   

DOI  :  10.1103/PhysRevB.106.245113

来源: SCIE

【 摘 要 】

We investigate the local moment formation in the half-filled SU(N) Hubbard model under a staggered ionic potential. As the Hubbard U increases, the charge fluctuations are suppressed and eventually frozen when U is above a critical value Uc, marking the development of well-defined local moment with integer m fermions on the A sublattice and (N - m) fermions on the B sublattice, respectively. We obtain an analytical solution for Uc for the paramagnetic ground state within the variational Gutzwiller approximation and renormalized mean field theory. For large N, Uc is found to depend on N linearly with fixed m/N, but sublinearly with fixed m. The local moment formation is accompanied by a peculiar phase transition from the band insulator to the Mott insulator, where the ionic potential and quasiparticle weight are renormalized to zero simultaneously. Inside the Mott phase, the low-energy physics is described by the SU(N) Heisenberg model with conjugate representations, which is widely studied in the literature.

【 授权许可】

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