Abstract
We study the zero-temperature magnetization process curve) of one-dimensional quantum antiferromagnets using a variant of the density-matrix renormalization group method. For both the zig-zag spin ladder and the bilinear-biquadratic chain, we find clear cusp-type singularities in the middle-field region of the curve. These singularities are successfully explained in terms of the double-minimum shape of the energy dispersion of the low-lying excitations. For the zig-zag spin ladder, we find that the cusp formation accompanies the Fermi-liquid to non-Fermi-liquid transition.
- Received 25 May 1999
DOI:https://doi.org/10.1103/PhysRevB.60.R6953
©1999 American Physical Society