Theoretical Study On Zero-field Splitting And Paramagnetic G-factor Of CdS:Cr²⁺ Crystal

CdS is a II-VI semiconductor,II-VI and III-V semiconductors doped with magnetic impurities?transition metal or rare earth ions?are important diluted magnetic semiconductors,which utilize the charge and spin properties of electrons to combine the characteristics of the semiconductor and magnetic materials.More specifically,it can combine the information processing property of semiconductors with the information storage function of magnetic materials,the advantages of semiconductor materials with the nonvolatile nature of magnetic materials.With the development of diluted magnetic semiconductor materials,a revolution is expected in the material science field.At the same time,diluted magnetic semiconductors are a bridge between magnetic physics and semiconductor physics,so that their development has a very important significance both in theory and in practical applications.It has thus become a hotspot in recent years.The problem of the zero-field splitting symbol of doped diluted magnetic semiconductors has never been thoroughly solved theoretically.This thesis utilizes the crystal field,EPR theory,and complete diagonalization method.Based on the double-ion wave function and ionic local structure,the CdS:Cr²⁺ spectrum structure,EPR factor g and zero-field splitting characterictics were obtained through our simulations.The results are consistent with experimental values.Our results demonstrate that for CdS:Cr²⁺ crystals,if only quintet states are taken into account,the zero-field splitting characteristics cannot be explained.Triplet states have a strong influence on the zero-field splitting.As for singlet states,their influence needs to be considered.The innovative work of this thesis can be summed up as follows: 1)A new formula is given for the zero-field splitting of CdS:Cr²⁺ crystals under D2 d symmetry,which solved the symbol problem encountered by previous investigators.2)The quantified influence of spin multiplets on the zero-field splitting of CdS:Cr²⁺ crystals was systematically investigated.3)It is the first time that a coherent explanation is given for the structure,spectrum,factor g and zero-field splitting of CdS:Cr²⁺ crystals.