Jun-ichiro KISHINE and Hidetoshi FUKUYAMA (Univ. Tokyo)
[J. Phys. Soc. Jpn. 66, 26 (1997)]
The temperature dependence of the static spin susceptibility, c, and NMR relaxation rate, T1-1, of S=1/2 Heisenberg two-leg ladder systems have been studied based on the Majorana fermion representation of the S=1/2 Heisenberg spin Hamiltonian introduced by Shelton, Nersesyan and Tsvelik. It is shown that, in the case of SrCu2O3, we can fit the experimental data of c and T1-1 in terms of the massive Majorana fermion excitation with mass m=440K to resolve the apparent discrepancy of the spin gap activation energies between (chi) and T1-1.