Excitations and finite-size properties of an integrable supersymmetric electronic model

• Autor(a) principal: Malvezzi, A. L. [UNESP]
• Data de Publicação: 2010
• Outros Autores: Martins, M. J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1103/PhysRevB.81.035120; http://hdl.handle.net/11449/225976

We investigate the bulk and finite-size properties of an integrable extension of the Hubbard model with a free parameter γ related to the quantum deformation of the superalgebra sl (2|2)(2). The Bethe ansatz solution is used to determine the ground state and the nature of the spin and charge excitations. As γ→0 the charge dispersion relation for low momenta crossover from linear to parabolic foreseeing a change from antiferromagnetic to ferromagnetic behavior. The study of the finite-size corrections to the spectrum reveals us that the underlying conformal theory has central charge c=-1 and a related effective central charge cef =2 as well as critical exponents depending on the parameter γ. We note that exact results at the isotropic point γ=0 can be established without recourse to the Bethe ansatz solution. © 2010 The American Physical Society.