Alternating-spin S=3/2 and sigma=1/2 Heisenberg chain with three-body exchange interactions

TL;DR

This paper investigates how three-body exchange interactions in an alternating S=3/2 and sigma=1/2 Heisenberg chain lead to diverse quantum spin states, including ferrimagnetic and gapped phases, using numerical density-matrix renormalization group methods.

Contribution

It demonstrates the emergence of various quantum phases in an alternating-spin chain due to three-body interactions, revealing a crossover between different Haldane-type states.

Findings

Identification of ferrimagnetic states

Discovery of a non-magnetic gapped phase

Observation of a crossover between spin-1 and spin-2 Haldane states

Abstract

The promotion of collinear classical spin configurations as well as the enhanced tendency towards nearest-neighbor clustering of the quantum spins are typical features of the frustrating isotropic three-body exchange interactions in Heisenberg spin systems. Based on numerical density-matrix renormalization group calculations, we demonstrate that these extra interactions in the Heisenberg chain constructed from alternating S=3/2 and sigma=1/2 site spins can generate numerous specific quantum spin states, including some partially-polarized ferrimagnetic states as well as a doubly-degenerate non-magnetic gapped phase. In the non-magnetic region of the phase diagram, the model describes a crossover between the spin-1 and spin-2 Haldane-type states.