We investigate the para-ferro magnetic transition of the repulsive SU(N) Hubbard model on a type of oneand two-dimensional decorated cubic lattices, referred as Tasaki lattices, which feature massive singleparticle gr...We investigate the para-ferro magnetic transition of the repulsive SU(N) Hubbard model on a type of oneand two-dimensional decorated cubic lattices, referred as Tasaki lattices, which feature massive singleparticle ground state degeneracy. Under certain restrictions for constructing localized many-particle ground states of flat-band ferromagnetism, the quantum model of strongly correlated electrons is mapped to a classical statistical geometric site-percolation problem, where the nontrivial weights of different configurations must be considered. We prove rigorously the existence of para-ferro transition for the SU(N) Hubbard model on one-dimensional Tasaki lattice and determine the critical density by the transfer-matrix method. In two dimensions, we numerically investigate the phase transition of SU(3),SU(4) and SU(10) Hubbard models by Metropolis Monte Carlo simulation. We find that the critical density exceeds that of standard percolation, and increases with spin degrees of freedom, implying that the effective repulsive interaction becomes stronger for larger N. We further rigorously prove the existence of flat-band ferromagnetism of the SUeNT Hubbard model when the number of particles equals to the degeneracy of the lowest band in the single-particle energy spectrum.展开更多
基金supported by the National Key R&D Program of China(2018YFA0306501)the National Natural Science Foundation of China(11434011,11522436,and 11774425)+4 种基金the Beijing Natural Science Foundation(Z180013)the Research Funds of Renmin University of China(10XNL016 and 16XNLQ03)supported in part by the National Key R&D Program of China(2017YFB0405700)the National Natural Science Foundation of China(11704267)start-up funding from Sichuan University(2018SCU12063)
文摘We investigate the para-ferro magnetic transition of the repulsive SU(N) Hubbard model on a type of oneand two-dimensional decorated cubic lattices, referred as Tasaki lattices, which feature massive singleparticle ground state degeneracy. Under certain restrictions for constructing localized many-particle ground states of flat-band ferromagnetism, the quantum model of strongly correlated electrons is mapped to a classical statistical geometric site-percolation problem, where the nontrivial weights of different configurations must be considered. We prove rigorously the existence of para-ferro transition for the SU(N) Hubbard model on one-dimensional Tasaki lattice and determine the critical density by the transfer-matrix method. In two dimensions, we numerically investigate the phase transition of SU(3),SU(4) and SU(10) Hubbard models by Metropolis Monte Carlo simulation. We find that the critical density exceeds that of standard percolation, and increases with spin degrees of freedom, implying that the effective repulsive interaction becomes stronger for larger N. We further rigorously prove the existence of flat-band ferromagnetism of the SUeNT Hubbard model when the number of particles equals to the degeneracy of the lowest band in the single-particle energy spectrum.
