Triplons, Magnons, and Spinons in a Single Quantum Spin System: SeCuO3

TL;DR

This study reveals that SeCuO3 hosts magnons, triplons, and spinons simultaneously, challenging the notion that these excitations are mutually exclusive, and provides a comprehensive magnetic model for this multi-excitation system.

Contribution

It demonstrates the coexistence of multiple excitation types in a single quantum spin system and identifies the minimal interactions responsible for this phenomenon.

Findings

Magnons, triplons, and spinons coexist in SeCuO3.

Neutron spectroscopy reveals the simultaneous presence of these excitations.

A minimal magnetic model with identified interactions explains the observations.

Abstract

Quantum spin systems exhibit an enormous range of collective excitations, but their spin waves, gapped triplons, fractional spinons, or yet other modes are generally held to be mutually exclusive. Here we show by neutron spectroscopy on SeCuO$_3$ that magnons, triplons, and spinons are present simultaneously. We demonstrate that this is a consequence of a structure consisting of two coupled subsystems and identify all the interactions of a minimal magnetic model. Our results serve qualitatively to open the field of multi-excitation spin systems and quantitatively to constrain the complete theoretical description of one member of this class of materials.