Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2010-06-18
Eur. Phys. J. B 77, 139-146 (2010)
Physics
Condensed Matter
Strongly Correlated Electrons
12 pages, 7 figures
Scientific paper
The elementary excitation spectrum of the spin-$\frac{1}{2}$ antiferromagnetic (AFM) Heisenberg chain is described in terms of a pair of freely propagating spinons. In the case of the Ising-like Heisenberg Hamiltonian spinons can be interpreted as domain walls (DWs) separating degenerate ground states. In dimension $d>1$, the issue of spinons as elementary excitations is still unsettled. In this paper, we study two spin-$\frac{1}{2}$ AFM ladder models in which the individual chains are described by the Ising-like Heisenberg Hamiltonian. The rung exchange interactions are assumed to be pure Ising-type in one case and Ising-like Heisenberg in the other. Using the low-energy effective Hamiltonian approach in a perturbative formulation, we show that the spinons are coupled in bound pairs. In the first model, the bound pairs are delocalized due to a four-spin ring exchange term in the effective Hamiltonian. The appropriate dynamic structure factor is calculated and the associated lineshape is found to be almost symmetric in contrast to the 1d case. In the case of the second model, the bound pair of spinons lowers its kinetic energy by propagating between chains. The results obtained are consistent with recent theoretical studies and experimental observations on ladder-like materials.
Bose Indrani
Pal Amit Kumar
No associations
LandOfFree
Motion of Bound Domain Walls in a Spin Ladder does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Motion of Bound Domain Walls in a Spin Ladder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motion of Bound Domain Walls in a Spin Ladder will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-260503