Threshold Phenomena under Photo Excitation of Spin-crossover Materials with Cooperativity due to Elastic Interactions

TL;DR

This paper investigates the threshold behavior of photo-induced spin state switching in spin-crossover materials, highlighting critical phenomena and finite-size effects due to elastic interactions.

Contribution

It introduces a model capturing elastic interactions in spin-crossover materials and analyzes the nonequilibrium critical behavior at the photo-excitation threshold.

Findings

Identification of a threshold light intensity inducing a phase transition.

Observation of mean-field spinodal critical behavior.

Finite-size scaling analysis of relaxation times.

Abstract

Photo-induced switching from the low-spin state to the high-spin state is studied in a model of spin-crossover materials, in which long-range interactions are induced by elastic distortions due to different molecular sizes the two spin states. At a threshold value of the light intensity we observe nonequilibrium critical behavior corresponding to a mean-field spinodal point. Finite-size scaling of the divergence of the relaxation time is revealed by analysis of kinetic Monte Carlo simulations.