Ground-State Spin of Hubbard Ladder Model with Infinite Electron Repulsion |

V.O. Cheranovskii
^{a}, E.V. Ezerskaya^{ a}, D.J. Klein^{ b} and V.V. Tokarev^{ a}^{a}V.N. Karazin Kharkiv National University, Svoboda Sq., 4, 61022 Kharkiv, Ukraine
^{b}Texas A&M University at Galveston, Galveston, TX, 77554 USA |

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We apply perturbation theory and cyclic spin permutation formalism to study the lowest energy states of the infinite-repulsion Hubbard model on n-leg ladders with alternating values of one-site energies α_{i} for neighboring rungs. We establish the "ferromagnetic" character of ladder ground-state at electron densities in the interval 1 - (2n)^{-1} ≤ ρ ≤ 1 and sufficiently large alternation of one-site energies of neighbor rungs of the ladder. We also show the stability of this state against the small deviations of the values of α_{i} in contrast to the case of two-leg ladder formed by weakly interacting neighbor rungs with equal one-site energies. |

DOI: 10.12693/APhysPolA.131.916 PACS numbers: 71.10.Fd, 75.10.Jm |