Ultrafast dynamics of light-induced spin crossovers under high pressure

TL;DR

This paper investigates the ultrafast non-equilibrium spin dynamics and phase behavior of a magnetic insulator with spin crossover under high pressure, revealing oscillatory relaxation phenomena and Franck Condon resonances.

Contribution

It provides a theoretical analysis of pressure-dependent phase diagrams and spin dynamics, highlighting the role of high pressure in modulating ultrafast spin crossover behavior.

Findings

Long-lived magnetization oscillations at low pressure

Sharp nonlinear oscillations near crossover pressure

Identification of Franck Condon resonances in spin dynamics

Abstract

Within the multielectron model of magnetic insulator with spin crossover under high pressure we have studied the mean field phase diagrams in pressure temperature plane and dynamics of a sudden excited non equilibrium spin state. We obtain the different relaxation of the magnetization, high spin/low spin occupation numbers, and the metal oxygen bond length for different values of the external pressure. We found the long living oscillations of magnetization without pressure and at small external pressure. Close to crossover pressure the smooth relaxation is accompanied with a set of sharp strongly non linear oscillations of magnetization and HS/LS occupation numbers that are accompanied by the Franck Condon resonances.