Partial Ferromagnetism in the Hubbard Chain with Next-Nearest-Neighbor Hopping

We study the one-dimensional Hubbard model with next-nearest-neighbor hopping by means of the numerical diagonalization for finite-size clusters. It is found that the ground state is evidently partially spin-polarized in a wide region of intermediate values of on-site Coulomb repulsion, which provides the first example as a minimal model without orbital degeneracy. Analysis of correlation functions makes it clear that the partially spin-polarized states form a spin polaron. Polaron's size grows with the increasing interaction.

[1]  Y. Kuramoto,et al.  Partial ferromagnetism in semimetallic systems: numerical calculation and rigorous proof , 2002 .

[2]  T. Momoi,et al.  Ferromagnetism in the one-dimensional Hubbard model with orbital degeneracy: From low to high electron density , 2001, cond-mat/0104223.

[3]  U. Tokyo,et al.  Existence of Saturated Ferromagnetic and Spiral States in 1D Lieb-Ferrimagnetic Models away from Half-Filling , 1999, cond-mat/9908144.

[4]  R. Arita,et al.  Spectral function of the spiral spin state in the trestle and ladder Hubbard model , 1998, cond-mat/9809084.

[5]  S. Daul,et al.  Ferromagnetic transition and phase diagram of the one-dimensional Hubbard model with next-nearest-neighbor hopping , 1997, cond-mat/9712310.

[6]  Faculty of Mathematics,et al.  Spatial Structure of Spin Polarons in the t-J Model , 1997, cond-mat/9712119.

[7]  S. Miyashita,et al.  New Saturated Ferromagnetism in the Flat-Band Hubbard Model in High Electron Filling , 1997 .

[8]  E. Müller-Hartmann.  Ferromagnetism in Hubbard models: Low density route , 1995, cond-mat/9502104.

[9]  Aoki,et al.  Scaling properties of the ferromagnetic state in the Hubbard model. , 1994, Physical review. B, Condensed matter.

[10]  Auerbach,et al.  Small-polaron theory of doped antiferromagnets. , 1991, Physical review letters.

[11]  Minoru Takahashi.  I=∞ Hubbard Model on Finite Lattices , 1982 .

[12]  G. Montambaux,et al.  Vacancies in a quantum crystal of fermions. The spin polaron in solid3He , 1982 .

[13]  Y. Nagaoka.  Ferromagnetism in a Narrow, Almost Half-Filled s Band , 1966 .

[14]  J. Kanamori,et al.  Electron Correlation and Ferromagnetism of Transition Metals , 1963 .