Collapsing Behavior of the Ferrimagnetic Ground State of the $S=1/2$ Heisenberg Antiferromagnet on the Lieb Lattice due to Frustration

TL;DR

This paper investigates how frustration in the $S=1/2$ Heisenberg antiferromagnet on the Lieb lattice causes a sudden collapse of ferrimagnetism, revealing multiple intermediate ground states with small magnetizations.

Contribution

It demonstrates a novel discontinuous collapse of ferrimagnetism due to frustration, with numerical evidence of intermediate states in the ground state magnetization.

Findings

Ferrimagnetism collapses discontinuously with frustration.

Intermediate ground states with small magnetizations are identified.

The collapse involves multiple magnetization states before complete disappearance.

Abstract

We study the $S = 1/2$ Heisenberg antiferromagnet on the Lieb lattice accompanied by additional interactions that create frustration. The system exhibits a ferrimagnetic ground state in the absence of frustration. Further, we successfully observe a novel type of collapsing behavior of the ferrimagnetism via numerical diagonalization. The ferrimagnetic state is observed to collapse in a discontinuous manner. Furthermore, different ground states with small spontaneous magnetizations are obtained before the spontaneous magnetization finally disappears.