Physical Review B
Exactly solvable supersymmetric t−J model with boundary hoppings and fields
Igor N. Karnaukhov
Abstract
The supersymmetric $t\text{\ensuremath{-}}J$ model with boundary hopping integrals and fields is proposed and solved exactly by means of the Bethe ansatz method. We find that for certain values of the boundary hopping integrals and fields the ground state contains boundary bound states, as new solutions of the Bethe ansatz equations in a charge sector called boundary charge strings. The boundary states define the thermodynamic properties of the boundary, such as the boundary charge, magnetic moment, that have been calculated numerically as a function of the magnetic field and chemical potential. We show that the boundary charge strings lead to a logarithmic divergent behavior of boundary magnetic moment in a weak magnetic field limit.