Temperature dependence of the electron and hole Land\'e g-factors in CsPbI3 nanocrystals in a glass matrix

TL;DR

This study investigates how the electron and hole Landé g-factors in CsPbI3 nanocrystals vary with temperature and size, revealing opposite trends and the influence of quantum confinement and thermal effects.

Contribution

It provides the first detailed analysis of temperature-dependent g-factors in CsPbI3 nanocrystals, linking size, energy, and temperature effects.

Findings

Electron g-factor decreases with size and temperature.

Hole g-factor increases with size and decreases with temperature.

G-factor variations are explained by energy dependence and thermal renormalization.

Abstract

The coherent spin dynamics of electrons and holes in CsPbI3 perovskite nanocrystals in a glass matrix are studied by the time-resolved Faraday ellipticity technique in magnetic fields up to 430 mT across a temperature range from 6 K up to 120 K. The Land\'e g-factors and spin dephasing times are evaluated from the observed Larmor precession of electron and hole spins. The nanocrystal size in the three studied samples varies from about 8 to 16 nm, resulting in exciton transition varying from 1.69 to 1.78 eV at the temperature of 6 K, allowing us to study the corresponding energy dependence of the g-factors. The electron g-factor decreases with increasing confinement energy in the NCs as result of NC size reduction, and also with increasing temperature. The hole g-factor shows the opposite trend. A model analysis shows that the variation of g-factors with NC size arises from the transition energy dependence of the g-factors, which becomes strongly renormalized by temperature.