Critical Behavior of Anisotropic Heisenberg Mixed-Spin Chains in a Field

TL;DR

This study numerically explores the critical behavior of anisotropic spin-(1,1/2) Heisenberg ferrimagnetic chains in a magnetic field, revealing stable magnetization plateaus and quantum effects influencing phase transitions.

Contribution

It provides new insights into the quantum critical phenomena and phase transitions in anisotropic mixed-spin chains under magnetic fields.

Findings

Stable magnetization plateau at one-third saturation in antiferromagnetic coupling.

Plateau vanishes via Kosterlitz-Thouless transition in ferromagnetic coupling.

Quantum effects significantly influence magnetization behavior.

Abstract

We numerically investigate the critical behavior of the spin-(1,1/2) Heisenberg ferrimagnet with anisotropic exchange coupling in a magnetic field. A quantized magnetization plateau as a function of the field, appearing at a third of the saturated magnetization, is stable over whole the antiferromagnetic coupling region. The plateau vanishes in the ferromagnetic coupling region via the Kosterlitz-Thouless transition. Comparing the quantum and classical magnetization curves, we elucidate what are essential quantum effects.