Collapse of Ferrimagnetism in Two-Dimensional Heisenberg Antiferromagnet due to Frustration

TL;DR

This paper investigates how frustration in a two-dimensional Heisenberg antiferromagnet causes the collapse of ferrimagnetism, revealing a transition to a nonmagnetic state with non-Lieb-Mattis ferrimagnetism characteristics.

Contribution

It demonstrates the continuous transition from Lieb-Mattis ferrimagnetism to a nonmagnetic phase due to frustration on the kagome lattice.

Findings

Spontaneous magnetization decreases continuously with frustration.

Intermediate state exhibits site-dependent local magnetization.

Transition from ferrimagnetic to nonmagnetic phase is continuous.

Abstract

We study ferrimagnetism in the ground state of the antiferromagnetic Heisenberg model on the spatially anisotropic kagome lattice, in which ferrimagnetism of the conventional Lieb-Mattis type appears in the region of weak frustration whereas the ground state is nonmagnetic in the isotropic case. Numerical diagonalizations of small finite-size clusters are carried out to examine the spontaneous magnetization. We find that the spontaneous magnetization changes continuously in the intermediate region between conventional ferrimagnetism and the nonmagnetic phase. Local magnetization of the intermediate state shows strong dependence on the site position, which suggests non-Lieb-Mattis ferrimagnetism.