The Research Of The Nuclear Growth And Electronic Properties Of Chiral Silicon Nanotubes

The geometric structural of nuclear cluster,the process of the nuclear cluster derived as well as the electronic properties of the chiral single-,double-,three wall silicon nanotubes were studied by using the density functional theory.The paper mainly includes the following parts.The paper describes the main process of the research in detail.At first,the nuclear cluster of the chiral silicon nanotubes is described.Secondly,the derivative rule of the chiral silicon nanoclusters is studied.The analysis shows that the process from the nuclear cluster derived the infinite chiral silicon nanotubes is through layer by layer growth mode.And then,through the binding energy,the stability and growth trend of the silicon clusters do further research.The analysis shows that with the increase of the length and the diameter,the silicon clusters are more stable,which illustrates that the nuclear cluster can be derived chiral silicon nanotubes.Finally,with the periodic boundary conditions,the structures of infinite chiral silicon nanotubes are obtained and their stability and electronic properties are discussed in detail.It shows that for the chiral single walled silicon nanotubes(SWSiNTs),the stability enhance further with the increase of the diameter.For the chiral doubel walled(DWSiNTs),with the increase of the wall spacing increasing,the stability of chiral DWSiNTs(n,n/2)@(2n,n)gradually enhances but the chiral DWSiNTs(2n,n)@(3n,3n/2)reduces;and with the diameter increasing the stability of chiral DWSiNTs gradually enhances.And the chiral SWSiNTs(n,m)show semiconductor properties when the chiral indexs are not multiple of 3,otherwise,they exhibit metal characteristic.In particular,the electronic properties of SWSi NTs(4,2)and(6,3)are abnormal due to the curvature effect.For chiral DWSiNTs and chiral TWSiNTs,the orderliness of band gaps is the same as SWSiNTs,that is when the chiral indexs for two tubes or three tubes are all multiple of 3,they show metal characteristic.It means the chiral indexs of just one tube are not multiple of 3,they exhibit semiconductors properties,except chiral DWSiNTs(4,2)@(8,4)and chiral TWSiNTs(4,2)@(8,4)@(12,6)which shows metal characteristic due to the curvature effect.A preliminary outlook on the development trend of the research is theoretical research for chiral silicon nanotubes can be used as a preliminary theory and method of exploration and accumulation,and provides an idea,experimental research and exploration direction,to pave the way for later study.