Compton profiles of NiO and TiO_2 obtained from first principles GWA spectral function

查看全文 作　　者：S M [1]Khidzir;M F M [1]Halid;W A T Wan [1]Abdullah 机构地区：[1]Department of Physics,Universiti of Malaya 出　　处：《Chinese Physics B》索引2016年第25卷第6期,共9页 摘　　要：In this work,we first use momentum density studies to understand strongly correlated electron behavior,which is typically seen in transition metal oxides.We observe that correlated electron behavior as seen in bulk NiO is due to the Fermi break located in the middle of overlapping spectral functions obtained from a GW(G is Green's function and W is the screened Coulomb interaction) approximation(GWA) calculation while in the case of TiO_2 we can see that the origin of the constant momentum distribution in lower momenta is due to a pile up of spectra before the Fermi energy.These observations are then used to compare our calculated Compton profiles with previous experimental studies of Fukamachi and Limandri.Our calculations for NiO are observed to follow the same trend as the experimental profile but it is seen to have a wide difference in the case of TiO_2 before the Fermi break.The ground state momentum densities differ significantly from the quasiparticle momentum density,thus stressing the importance of the quasiparticle wave function as the input for the study of charge density and the electron localization function.Finally we perform a calculation of the quasiparticle renormalization function,giving a quantitative description of the discontinuity of the GWA momentum density. 关 键 词：TiO2 谱函数 NIO 康普顿 第一性原理 型材 过渡金属氧化物 GREEN函数