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 ar...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）.展开更多
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 ...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 mononitridcs, 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 0.142 eV 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.展开更多
We have preformed systematical ab initio studies of the structural and electronic properties of short-period Si1-xⅣx/Si （x = 0.125, 0.25, 0.5, Ⅳ=Ge, Sn） superlattices （SLs） grown along the [001] direction on bul...We have preformed systematical ab initio studies of the structural and electronic properties of short-period Si1-xⅣx/Si （x = 0.125, 0.25, 0.5, Ⅳ=Ge, Sn） superlattices （SLs） grown along the [001] direction on bulk Si. The present calculations reveal that the Si0.875Ge0.125/Si, Si0.75Ge0.25/Si and Si0.875Sn0.125/Si are the F-point direct bandgap semiconductors. The technological importance lies in the expectation that the direct gap Si1-xⅣx/Si SLs may be used as components in integrated optoelectronic devices, in conjunction with the already well-established and highly advanced silicon technology.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10274946 and 60336010.
文摘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）.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10274946 and 60336010）.
文摘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 mononitridcs, 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 0.142 eV 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.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10274946 and 60336010.
文摘We have preformed systematical ab initio studies of the structural and electronic properties of short-period Si1-xⅣx/Si （x = 0.125, 0.25, 0.5, Ⅳ=Ge, Sn） superlattices （SLs） grown along the [001] direction on bulk Si. The present calculations reveal that the Si0.875Ge0.125/Si, Si0.75Ge0.25/Si and Si0.875Sn0.125/Si are the F-point direct bandgap semiconductors. The technological importance lies in the expectation that the direct gap Si1-xⅣx/Si SLs may be used as components in integrated optoelectronic devices, in conjunction with the already well-established and highly advanced silicon technology.
