RE2SiO5(RE=Sc,Y,La)结构稳定性及掺杂效应的理论研究OA

Rare earth silicates RE2SiO5(RE=rare earth)with significant applications as laser host,scintillator,thermal barrier coatings,and quantum memory devices,generally exhibit two distinct structural phases:X1-type(lower temperature,space group P21/c)and X2-type(higher temperature,space group C2/c).Each structure contains two unique sites hosting the rare earth ions,characterized by different coordination numbers(CNs).Theoretical calculations with the electronic structure and molecular dynamics software package CP2K were performed to better understand the structural stabilities of these compounds and the preferential site occupations of doping rare earth ions.The Gaussian basis set and the Perdew-Burke-Ernzerhof for solids(PBEsol)functional were employed due to their high computation speed and their reliable structural optimization results for solid materials.According to the results from theoretical calculations,it is found that the dispersion correction plays a vital role in correctly predicting the relative structural stability of the RE2SiO5 phases.Furthermore,the doping behaviors of rare earth ions with varying sizes in Y2SiO5 are systematically investigated.Our findings reveal that in both phases,Y1 site(CN=9 for X1-type,and CN=7 for X2-type)is preferentially occupied by larger ions like La3+,while smaller ions such as Sc3+demonstrate greater stability at Y2 site(CN=7 for X1-type,and CN=6 for X2-type).These results provide valuable insights into the structural properties and doping mechanisms of this class of crystals.