paper

Critical properties of S=1/2 Heisenberg ladders in magnetic fields

arXiv:cond-mat/9809088 · doi:10.1103/PhysRevB.58.14401

Abstract

The critical properties of the $S = 1/2$ Heisenberg two-leg ladders are investigated in a magnetic field. Combining the exact diagonalization method and the finite-size-scaling analysis based on conformal field theory, we calculate the critical exponents of spin correlation functions numerically. For a strong interchain coupling, magnetization dependence of the critical exponents shows characteristic behavior depending on the sign of the interchain coupling. We also calculate the critical exponents for the $S = 1/2$ Heisenberg two-leg ladder with a diagonal interaction, which is thought as a model Hamiltonian of the organic spin ladder compound $C u_{2} (1, 4 - d ia z a cy c l o h e pt an e)_{2} C l_{4}$ . Numerical results are compared with experimental results of temperature dependence of the NMR relaxation rate $1/ T_{1}$ .

REVTeX, 10 pages, 8 figures, accepted for Phys. Rev. B