Crystal field tuned spin-flip luminescence in NiPS3

TL;DR

This study investigates the spin-flip luminescence in NiPS3, revealing how magnetic and crystal field effects influence optical properties, with implications for magnetic optoelectronic applications.

Contribution

It provides experimental and theoretical insights into the origin of luminescence in NiPS3 and demonstrates how substitutions affect its magnetic and optical behavior.

Findings

Luminescence linked to magnetic ground state changes

Substitutions alter Neel transition temperature and luminescence

Crystal field calculations explain the excitation origin

Abstract

Layered magnetic materials potentially hold the key to future applications based on optical control and manipulation of magnetism. NiPS3, a prototype member of this family, is antiferromagnetic below 155 K and exhibits sharp photoluminescence associated to a transition between a triplet ground state and a singlet excited state. The nature of the luminescent transition is a matter of current debate and so is an eventual fundamental link of this excitation to magnetism. Here we provide answers through experiments and calculations. We fabricate samples with metal and ligand substitutions which alter the Neel transition temperature and measure the effects of these changes on the temperature dependent photoluminescence. We perform crystal field and charge transfer multiplet calculations to explain the origin of the excitation and identify the effects of the magnetic ground state on its properties. These measurements and calculations provide a comprehensive explanation for the observed properties and a template for finding similar materials exhibiting spin-flip luminescence.