Dimer states in the one-dimensionalt-J-J’ model
Ken'ichi Takano, Kazuhiro Sano
We introduced variational wave functions to describe dimer states in the one-dimensional t-J-J' model, when one hole is doped and J'=J/2. For finite J/\ensuremath{\Vert}t\ensuremath{\Vert} in the first excited state with S=1, there exists a bound state of the hole and an unpaired electron. For the choice of J/\ensuremath{\Vert}t\ensuremath{\Vert}=2, the spin gap is ${\mathrm{\ensuremath{\Delta}}}^{\mathrm{var}}$=0.181J and is smaller than the value of the corresponding spin system, ${\mathrm{\ensuremath{\Delta}}}_{0}^{\mathrm{var}}$=0.25J. The existence of the bound state suggests that the excited state as a function of the electron density is discontinuous at half-filling if J/\ensuremath{\Vert}t\ensuremath{\Vert} is finite.
Physical review. B, Condensed matter•Oct 1, 1993•9 citations