(Received October 11, 1999)
Quantum critical behavior in the magnetization process of alternating-spin chains is studied by the exact diagonalization and the size scaling technique based on the conformal field theory. The plateau at the spontaneous magnetization is revealed to vanish due to the anisotropy at the Kosterlitz-Thouless transition point in the ferromagnetic region. It is also found that the bond alternation creates a novel plateau as an essential quantum effect.
URL : http://ptp.ipap.jp/link?PTPS/138/513/
DOI : 10.1143/PTPS.138.513