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We calculate the band structure of BaS using the local density approximation and the GW approximation ( G WA ), i.e. in combination of the Green function G and the screened Coulomb interaction W, The Ba 4d states are treated as valence states. We find that BaS is a direct band-gap semiconductor, The result shows that the GWA band gap (Eg-Gw = 3.921 eV) agrees excellently with the experimental result (Eg-EXPT = 3.88 eV or 3.9eV). 相似文献
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运用标准的准粒子GW方法重新考察了BaSe的准粒子能带结构.为便于比较,同时计算了局域密度近似(LDA)和广义梯度近似(GGA)下的能带.结果表明,LDA和GGA方法都不能准确描述这个材料的带隙.与实验测量值对比,其误差分别达到39.9%和32.6%.GW准粒子能带的结果则可以对其带隙作出大幅度的修正,得到与实验测量相当符合的理论结果.与已有的计算结果不同,B1结构BaSe准粒子能带具有Γ点直接带隙特性,表明在Ba价电子组态中考虑4d电子的作用至关重要.
关键词:
BaSe
GW
能带结构
带隙 相似文献
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Electronic structure of ScN and YN: density-functional theory LDA and GW approximation calculations 下载免费PDF全文
The desirable physical properties of hardness, high temperature
stability, and conductivity make the early transition metal nitrides
important materials for various technological applications. To learn
more about the nature of these materials, the local-density
approximation(LDA) and GW approximation i.e. combination of the
Green function G and the screened Coulomb interaction W, have been
performed. This paper investigates the bulk electronic and physical
properties of early transition metal mononitrides, ScN and YN in the
rocksalt structure. In this paper, the semicore electrons are
regarded as valance electrons. ScN appears to be a semimetal, and YN
is semiconductor with band gap of 0.142eV within the LDA, but are
in fact semiconductors with indirect band gaps of 1.244 and
0.544\,eV respectively, as revealed by calculations performed using
GW approximation. 相似文献
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