Ferrimagnetic and Long Period Antiferromagnetic Phases in High Spin Heisenberg Chains with D-Modulation

TL;DR

This paper investigates the ground state phases of high spin Heisenberg chains with alternating anisotropy, revealing ferrimagnetic states, phase transitions, and fractional magnetization locking, using numerical methods.

Contribution

It introduces a detailed numerical analysis of ferrimagnetic and antiferromagnetic phases in high spin chains with D-modulation, highlighting new phase behaviors and magnetization properties.

Findings

Ferrimagnetic phase appears between Haldane and Neel phases for integer spins.

Transition from Tomonaga-Luttinger liquid to ferrimagnetic state in half-odd-integer spins.

Fractional magnetization values satisfy Oshikawa-Yamanaka-Affleck condition.

Abstract

The ground state properties of the high spin Heisenberg chains with alternating single site anisotropy are investigated by means of the numerical exact daigonaization and DMRG method. It is found that the ferrimagnetic state appears between the Haldane phase and period doubled N\'eel phase for the integer spin chains. On the other hand, the transition from the Tomonaga-Luttinger liquid state into the ferrimagnetic state takes place for the half-odd-integer spin chains. In the ferrimagnetic phase, the spontaneous magnetization varies continuously with the modulation amplitude of the single site anisotropy. Eventually, the magnetization is locked to fractional values of the saturated magnetization. These fractional values satisfy the Oshikawa-Yamanaka-Affleck condition. The local spin profile is calculated to reveal the physical nature of each state. In contrast to the case of frustration induced ferrimagnetism, no incommensurate magnetic superstructure is found.