Le Journal de Physique Colloques
DISORDER LINE IN A QUANTUM SPIN CHAIN WITH COMPETING INTERACTIONS
I. Harada, Tsukasa Kimura, Takashi Tonegawa
Abstract
The spin-1/2 Heisenberg chain with antiferromagnetic first- and second-neighbor interactions is studied by the cluster transfer-matrix method. It is found that this quantum model exhibits a disorder temperature above which the spin correlation function decays with an incommensurate oscillation while below which it decays antiferromagnetically.