Laser-induced Transition Metal Oxide X_mO_n^+/0 (X=V,Cr;m,n=2,3) Clusters Investigation Of Ultrafast Spin Dynamics On Clusters

In recent years,with the development of industrial demand for high access speed and high storage density of magnetic media,research on laser-induced ultrafast magnetization dynamics has attracted the attention of many experimental and theoretical research groups at home and abroad.Therefore,it is an inevitable trend for the future development of electronic devices to satisfy both high access speed and high storage density.The first-principles of quantum chemistry is used to study the ultrafast spin dynamics of magnetic clusters.Theoretically,the ultrafast manipulation based on spin degrees of freedom provides a reference for the design of magnetic storage.This article takes vanadium oxides V2O2,V2O3,V3O2+,V3O3+,and chromium oxides Cr2O2,Cr2O3,Cr3O2,Cr3O3 as research objects.After geometric structure optimization calculation,and frequency calculation verification,the corresponding stable structure is finally determined.Through the electronic energy levels of the eight kinds of transition metal oxides of cluster have been analysised,and based on the theory of ? process models to predict the achievable of ultrafast spin dynamics induced by laser pulse.The main research work and conclusion of this paper include the following three aspects:(1)Combined with the ? process theoretical model and the self-made genetic algorithm program of the W.Hübner's research group,for the four clusters of VmOn(+/0)(m,n=2,3),we have selected the structure of spin multiplicity M=5 for relevant calculations(infrared spectrum,electron energy level,spin dynamics)were performed,and spin states below 2.5 eV were selected for spin dynamics studies by Symmetry Adapted Cluster-Configuration Interaction(SAC-CI),and the spin flip dynamics that can be achieved by the quintet state were predicted.Among them,we found that the spin-flip dynamics of the expected value of spin from(S)=-2 to(S)=2 on V2O3 clusters was achieved,and the transfer rate was as high as 95.3%or more,which was difficult to achieve in our previous work.The dynamics implemented on V2O3 clusters fill this gap in magnetization manipulation,and provide diversity for designing electronic devices of different materials.(2)At the same time,Spin expected value from...