Frustration-Induced Ferrimagnetism in S=1/2 Heisenberg Spin Chain

TL;DR

This study reveals that ferrimagnetism can occur in a frustrated S=1/2 Heisenberg spin chain without a multi-sublattice structure, identifying two distinct ferrimagnetic phases through numerical methods.

Contribution

It demonstrates the emergence of ferrimagnetism in a frustrated spin chain without the need for a multi-sublattice structure, introducing a nontrivial ferrimagnetic phase.

Findings

Ferrimagnetism appears in the ground state despite the absence of a multi-sublattice structure.

Two types of ferrimagnetic phases are identified: Lieb-Mattis type and a nontrivial phase.

Numerical methods confirm the realization of these phases in the model.

Abstract

The ground-state properties of the S=1/2 frustrated Heisenberg spin chain with interactions up to fourth nearest neighbors are investigated by the exact-diagonalization method and density matrix renormalization group method. Our numerical calculations clarify that the ferrimagnetic state is realized in the ground state in spite of the fact that a multi-sublattice structure in the shape of the system is absent. We find that there are two types of ferrimagnetic phases: one is the well-known ferrimagnetic phase of the Lieb-Mattis type and the other is the nontrivial ferrimagnetic phase that is different from that of the Lieb-Mattis type. Our results suggest that a multi-sublattice structure of the shape is not necessarily required for the occurrence of ferrimagnetism.