采用基于第一性原理下的局域密度近似(LDA)方法对岩石矿物结构Ca硫族化合物CaX(X=S, Se, Te)的晶格常数和电子结构进行了研究.研究结果表明,使用LDA方法得到的晶格常数与实验值符合得很好,但带隙值却远低于实验值.为了获得可靠的带隙值...采用基于第一性原理下的局域密度近似(LDA)方法对岩石矿物结构Ca硫族化合物CaX(X=S, Se, Te)的晶格常数和电子结构进行了研究.研究结果表明,使用LDA方法得到的晶格常数与实验值符合得很好,但带隙值却远低于实验值.为了获得可靠的带隙值,使用了GW(G格林函数, W库伦屏蔽相互作用)近似方法对Ca硫族化合物的带隙进行修正.利用GW近似方法计算CaS和CaSe的带隙值比利用LDA计算的带隙值高,并且与实验值相吻合.同时也预测了CaTe的带隙值,尽管没有实验值作为参考,但GW近似计算的结果应该是合适的值.展开更多
Similar to most of the other alkaline earth elements,barium atoms can be candidates for optical clocks,thus the magic wavelength for an optical lattice is important for the clock transition.We calculate the magic wave...Similar to most of the other alkaline earth elements,barium atoms can be candidates for optical clocks,thus the magic wavelength for an optical lattice is important for the clock transition.We calculate the magic wavelength of a possible clock transition between 6s21S0 and 6s5d3D2 states of barium atoms.Our theoretical result shows that there are three magic wavelengths 615.9 nm,641.2 nm and 678.8 nm for a linearly polarized optical lattice laser for barium.展开更多
文摘采用基于第一性原理下的局域密度近似(LDA)方法对岩石矿物结构Ca硫族化合物CaX(X=S, Se, Te)的晶格常数和电子结构进行了研究.研究结果表明,使用LDA方法得到的晶格常数与实验值符合得很好,但带隙值却远低于实验值.为了获得可靠的带隙值,使用了GW(G格林函数, W库伦屏蔽相互作用)近似方法对Ca硫族化合物的带隙进行修正.利用GW近似方法计算CaS和CaSe的带隙值比利用LDA计算的带隙值高,并且与实验值相吻合.同时也预测了CaTe的带隙值,尽管没有实验值作为参考,但GW近似计算的结果应该是合适的值.
基金by the National Natural Science Foundation of China under Grant Nos 11004227 and 11074281the National Basic Research Program of China under Grant No 2010CB832805,and the Chinese Academy of Sciences.
文摘Similar to most of the other alkaline earth elements,barium atoms can be candidates for optical clocks,thus the magic wavelength for an optical lattice is important for the clock transition.We calculate the magic wavelength of a possible clock transition between 6s21S0 and 6s5d3D2 states of barium atoms.Our theoretical result shows that there are three magic wavelengths 615.9 nm,641.2 nm and 678.8 nm for a linearly polarized optical lattice laser for barium.
