Diamond chains with multiple-spin exchange interactions

TL;DR

This paper explores the complex phase diagram of a spin-1/2 Heisenberg diamond chain with four-spin interactions, revealing multiple novel phases and phase transitions through numerical analysis.

Contribution

It introduces a detailed analysis of the phase diagram including new tetramer-dimer and dimerized phases in the presence of cyclic four-spin exchange interactions.

Findings

Identification of multiple spin phases including tetramer-dimer and dimerized phases.

Discovery of an exotic four-fold degenerate dimerized phase.

Characterization of quantum phase transitions between these phases.

Abstract

We study the phase diagram of a symmetric spin-1/2 Heisenberg diamond chain with additional cyclic four-spin exchange interactions. The presented analysis supplemented by numerical exact-diagonalization results for finite periodic clusters implies a rich phase diagram containing, apart from standard magnetic and spin-liquid phases, two different tetramer-dimer phases as well as an exotic four-fold degenerate dimerized phase. The characteristics of the established spin phases as well as the nature of quantum phase transitions are discussed, as well.