Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2009-06-24
Physical Review B 80, 014405 (2009)
Physics
Condensed Matter
Strongly Correlated Electrons
15 pages, 11 figures, to appear in Phys. Rev. B
Scientific paper
10.1103/PhysRevB.80.014405
We introduce a spin ladder with antiferromagnetic Ising ZZ interactions along the legs, and interactions on the rungs which interpolate between the Ising ladder and the quantum compass ladder. We show that the entire energy spectrum of the ladder may be determined exactly for finite number of spins 2N by mapping to the quantum Ising chain and using Jordan-Wigner transformation in invariant subspaces. We also demonstrate that subspaces with spin defects lead to excited states using finite size scaling, and the ground state corresponds to the quantum Ising model without defects. At the quantum phase transition to maximally frustrated interactions of the compass ladder, the ZZ spin correlation function on the rungs collapses to zero and the ground state degeneracy increases by 2. We formulate a systematic method to calculate the partition function for a mesoscopic system, and employ it to demonstrate that fragmentation of the compass ladder by kink defects increases with increasing temperature. The obtained heat capacity of a large compass ladder consisting of 2N=104 spins reveals two relevant energy scales and has a broad maximum due to dense energy spectrum. The present exact results elucidate the nature of the quantum phase transition from ordered to disordered ground state found in the compass model in two dimensions.
Brzezicki Wojciech
Oles' Andrzej M.
No associations
LandOfFree
Exact solution for a quantum compass 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 Exact solution for a quantum compass ladder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exact solution for a quantum compass ladder will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-105919