Abstract
We present numerical results for the magnetic susceptibility of a Heisenberg antiferromagnetic spin ladder as a function of temperature and the spin-spin interaction strengths and . These are contrasted with bulk-limit results for the dimer chain. A fit to the experimental susceptibility of the candidate spin-ladder compound vanadyl pyrophosphate, (VO, gives the parameters =7.82 meV and =7.76 meV. With these values we predict a singlet-triplet energy gap of =3.9 meV, and give a numerical estimate of the ladder triplet dispersion relation ω(k). In contrast, a fit to the dimer-chain model leads to =11.11 meV and =8.02 meV, which predicts a gap of =4.9 meV.
- Received 15 April 1994
DOI:https://doi.org/10.1103/PhysRevB.50.6817
©1994 American Physical Society