Finite-size clusters in discrete Hubbard model with transverse and longitudinal magnetic fields

• Published in: Physica. B, Condensed matter Vol. 259; pp. 736 - 738
• Main Authors: Kocharian, A.N, Jermakian, A.K, Saakian, A.S
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1999
• Subjects: Mott–Hubbard crossover; Peierls phase; Peierls phase; Mott–Hubbard crossover
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(98)00918-1

We study the finite-size effects and stability of the fully polarized ferromagnetic state against one spin-flip in the presence of a strong magnetic field (Zeeman coupling) in a finite Hubbard lattice for 1d and 2d clusters of atoms. Periodic boundary conditions for electrons is assumed and we thread the system with a flux (Peierls phase) which is represented by a transverse magnetic field normal to the surface. The exact critical magnetic field for ferromagnetic saturation at half-filling depends on cluster size, intra-atomic interaction and transverse field. It is found that the excitation gap and the criteria for Mott–Hubbard localization in the high spin region for small systems in 1d and 2d depend on lattice geometry, the number of atomic sites (parity) and Peierls phase.