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

Abstract

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 $U_c$, 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 $U_c$ for the paramagnetic ground state within the variational Gutzwiller approximation and renormalized mean field theory. For large $N$, $U_c$ 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.

9 pages, 4 figures

References in corpus (22)

• Many-Body Physics with Ultracold Gases
• Observation of antiferromagnetic correlations in the Hubbard model with ultracold atoms
• Spectroscopic observation of SU(N)-symmetric interactions in Sr orbital magnetism
• An SU(N) Mott insulator of an atomic Fermi gas realized by large-spin Pomeranchuk cooling
• Ultracold Fermi Gases with Emergent SU(N) Symmetry
• Ultracold fermions and the SU(N) Hubbard model
• Néel and Spin-Peierls ground states of two-dimensional SU(N) quantum antiferromagnets
• Observation of antiferromagnetic correlations in an ultracold SU($N$) Hubbard model
• Coherent multi-flavour spin dynamics in a fermionic quantum gas
• Resonating plaquette phases in large spin cold atom systems
• Exact Diagonalization of Heisenberg SU(N) models
• Simplex solids in SU(N) Heisenberg models on the kagome and checkerboard lattices
• Thermodynamics of a deeply degenerate SU($N$)-symmetric Fermi gas
• Simplex solid states of SU(N) quantum antiferromagnets
• Ground States of the SU(N) Heisenberg Model
• Exotic many-body physics with large-spin Fermi gases
• Quantum Monte Carlo simulation of thermodynamic properties of SU(2N) ultracold fermions in optical lattices
• Quantum magnetism of ultra-cold fermion systems with the symplectic symmetry
• Variational Monte-Carlo investigation of SU($N$) Heisenberg chains
• Finite-temperature valence-bond-solid transitions and thermodynamic properties of interacting SU($2N$) Dirac fermions
• Is there a superconducting phase in the half-filled ionic Hubbard model ?
• Thermal Phase Transition of Generalized Heisenberg Models for SU(N) Spins on Square and Honeycomb Lattices

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• Unit-density SU(3) Fermi-Hubbard Model with Spin Flavor Imbalance