Finite-size scaling for low-energy excitations in integer Heisenberg spin chains | |
Article | |
关键词: ONE-DIMENSIONAL ANTIFERROMAGNETS; QUANTUM RENORMALIZATION-GROUPS; HALDANE-GAP; BOSE-CONDENSATION; FIELD-THEORY; EDGE STATES; MONTE-CARLO; MAGNETIZATION; | |
DOI : 10.1103/PhysRevB.55.2721 | |
来源: SCIE |
【 摘 要 】
In this paper we study the finite-size scaling for low-energy excitations of S = 1 and S = 2 Heisenberg chains, using the density matrix renormalization-group technique. A crossover from 1/L behavior (with L as the chain length) for medium chain length to 1/L(2) scaling for long chain length is found for excitations in the continuum band as the length of the open chain increases. Topological spin S=1/2 excitations are shown to give rise to the two lowest energy states for both open and periodic S=1 chains. In periodic chains these two excitations are ''confined'' next to each other, while for open chains they are two free-edge 1/2 spins. The finite-size scaling of the two lowest energy excitations of open S=2 chains is determined by coupling the two free-edge S=1 spins. The gap and correlation length for S=2 open Heisenberg chains are shown to be 0.082 (in units of the exchange J) and 47, respectively.
【 授权许可】
Free