We perform the calculations on geometric and electronic structures of Si-doped heterofullerene C5oSi10 and its derivatives, a C40Si20-C40Si20 dimer and a C40Si20-based nanowire by using density-functional theory, The ...We perform the calculations on geometric and electronic structures of Si-doped heterofullerene C5oSi10 and its derivatives, a C40Si20-C40Si20 dimer and a C40Si20-based nanowire by using density-functional theory, The optimized configuration of the C40Si20-based nanowire exhibits a regular dumbbell-shaped chain nanostructure. The electronic structure calculations indicate that the HOMO-LUMO gaps of the heterofullerene-based materials can be greatly modified by substitutionally doping with Si atoms and show a decreasing trend with increase cluster size. Unlike the band structures of the conventional wide band gap silicon carbide nanomaterials, the C40Si20- based nanowire has a very narrow direct band gap of 0.087eV.展开更多
We theoretically show that H atoms can be chemically adsorbed onto the surface of the Si-C heterofullerene- based nanotubes. The adsorbing energy of the H atom on Si-C heterofullerene-based nanotubes is in the range o...We theoretically show that H atoms can be chemically adsorbed onto the surface of the Si-C heterofullerene- based nanotubes. The adsorbing energy of the H atom on Si-C heterofullerene-based nanotubes is in the range of 4.28-5.66 eV without any barrier for the H atom to approach to the Si-C heterofullerene-based nanotubes. The band-gap of Si-C heterofullerene-based nanotubes can be dramatically modified by introducing dopant states, i.e., there is a transition from semiconductor to conductor of the Si-C heterofullerene-based nanotubes induced by the adsorption of the H atom. These results actually open a way to tune electronic properties of heterofullerene-based nanotubes and thus may propose an efficient pathway for band structure engineering.展开更多
Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized t...Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.展开更多
We perform ab initio calculations on the self-assembled base-functionalized single-walled carbon nanotubes （SWNTs） which exhibit the quasi-1D ‘ladder＇ structure. The optimized configuration in the ab initio calcul...We perform ab initio calculations on the self-assembled base-functionalized single-walled carbon nanotubes （SWNTs） which exhibit the quasi-1D ‘ladder＇ structure. The optimized configuration in the ab initio calculation is very similar to that obtained from molecular dynamics simulation. We also calculate the electronic structures of the self-assembled base-functionalized SWNTs that exhibit distinct difference from the single-branch base-functionalized SWNT with a localized state lying just below the Fermi level, which may result from the coupling interaction between the bases accompanied by the self-assembly behaviour.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10675075, 50402017 and 10604039, the National Basic Research Programme of China under Grant No 2005CB623602, the Program for New Century Excellent Talents in University of China, the Outstanding Youth Scientist Research Foundation of Shandong Province, and the Foundation of Ministry of Education of China under Grant Nos 2006BS04012 and 20050422006, and the Excellent Middle-Aged and Young Scientist Award Foundation of Shandong Province under Grant No 2004BS5007.
文摘We perform the calculations on geometric and electronic structures of Si-doped heterofullerene C5oSi10 and its derivatives, a C40Si20-C40Si20 dimer and a C40Si20-based nanowire by using density-functional theory, The optimized configuration of the C40Si20-based nanowire exhibits a regular dumbbell-shaped chain nanostructure. The electronic structure calculations indicate that the HOMO-LUMO gaps of the heterofullerene-based materials can be greatly modified by substitutionally doping with Si atoms and show a decreasing trend with increase cluster size. Unlike the band structures of the conventional wide band gap silicon carbide nanomaterials, the C40Si20- based nanowire has a very narrow direct band gap of 0.087eV.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50525206 and U0734004, and the Ministry of Education （106126）, the Postdoctoral Science Foundation of China under Grant No 20090450903, and Shanghai Supercomputer Center.
文摘We theoretically show that H atoms can be chemically adsorbed onto the surface of the Si-C heterofullerene- based nanotubes. The adsorbing energy of the H atom on Si-C heterofullerene-based nanotubes is in the range of 4.28-5.66 eV without any barrier for the H atom to approach to the Si-C heterofullerene-based nanotubes. The band-gap of Si-C heterofullerene-based nanotubes can be dramatically modified by introducing dopant states, i.e., there is a transition from semiconductor to conductor of the Si-C heterofullerene-based nanotubes induced by the adsorption of the H atom. These results actually open a way to tune electronic properties of heterofullerene-based nanotubes and thus may propose an efficient pathway for band structure engineering.
基金Project supported by Guangdong Basic and Applied Basic Research Foundation(Grant No.2019A1515011227)the National Natural Science Foundation of China(Grant No.51902353)+1 种基金the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(Grant No.22lgqb03)the Fund from the State Key Laboratory of Optoelectronic Materials and Technologies(Grant No.OEMT-2022-ZRC-01)
文摘Polyyne,an sp~1-hybridized linear allotrope of carbon,has a tunable quasiparticle energy gap,which depends on the terminated chemical ending groups as well as the chain length.Previously,nitrogen doping was utilized to tailor the properties of different kinds of allotrope of carbon.However,how the nitrogen doping tailors the properties of the polyyne remains unexplored.Here,we applied the GW method to study the quasiparticle energy gaps of the N-doped polyynes with different lengths.When a C atom is substituted by an N atom in a polyyne,the quasiparticle energy gap varies with the substituted position in the polyyne.The modification is particularly pronounced when the second-nearest-neighboring carbon atom of a hydrogen atom is substituted.In addition,the nitrogen doping makes the Fermi level closer to the lowest unoccupied molecular orbital,resulting in an n-type semiconductor.Our results suggest another route to tailor the electronic properties of polyyne in addition to the length of polyyne and the terminated chemical ending groups.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10374059 and 50402017, the National Basic Research Programme of China under Grant No 2005CB623602, the Foundation of Education Ministry of China under Grant Nos 20020422012 and 20050422006, and the Excellent Middle-Aged and Young Scientist Award Foundation of Shandong Province under Grant No 2004BS5007.
文摘We perform ab initio calculations on the self-assembled base-functionalized single-walled carbon nanotubes （SWNTs） which exhibit the quasi-1D ‘ladder＇ structure. The optimized configuration in the ab initio calculation is very similar to that obtained from molecular dynamics simulation. We also calculate the electronic structures of the self-assembled base-functionalized SWNTs that exhibit distinct difference from the single-branch base-functionalized SWNT with a localized state lying just below the Fermi level, which may result from the coupling interaction between the bases accompanied by the self-assembly behaviour.
