Magnetization Process of the Spin-1/2 Triangular-Lattice Heisenberg Antiferromagnet with Next-Nearest-Neighbor Interactions -- Plateau or Nonplateau

TL;DR

This study uses numerical diagonalization to explore how next-nearest-neighbor interactions affect the magnetization plateau in a spin-1/2 triangular-lattice Heisenberg antiferromagnet, revealing a nonplateau region between plateau phases.

Contribution

It demonstrates the emergence of a nonplateau region between known magnetization plateaus as the next-nearest-neighbor interaction strength varies.

Findings

Magnetization plateau at one-third saturation exists in both weak and strong interaction regimes.

A nonplateau region appears between plateau phases when interactions are varied.

The stability of the plateau is affected by the amplitude of next-nearest-neighbor interactions.

Abstract

An $S=1/2$ triangular-lattice Heisenberg antiferromagnet with next-nearest-neighbor interactions is investigated under a magnetic field by the numerical-diagonalization method. It is known that, in both cases of weak and strong next-nearest-neighbor interactions, this system reveals a magnetization plateau at one-third of the saturated magnetization. We examine the stability of this magnetization plateau when the amplitude of next-nearest-neighbor interactions is varied. We find that a nonplateau region appears between the plateau phases in the cases of weak and strong next-nearest-neighbor interactions.