A magnetic ground state is revealed for the first time in zigzag-edged carbon nanoscrolls(ZCNSs)from spin-unrestricted density functional theory calculations.Unlike their flat counterpart-zigzag-edged carbon nanoribbo...A magnetic ground state is revealed for the first time in zigzag-edged carbon nanoscrolls(ZCNSs)from spin-unrestricted density functional theory calculations.Unlike their flat counterpart-zigzag-edged carbon nanoribbons,which are semiconductors with spin-degenerate electronic structure-ZCNSs show a variety of magnetic configurations,namely spin-selective semiconductors,metals,semimetals,quasi-half-metals,and half-metals.To the best of our knowledge,this is the first discovery of quasi-half-metals and half-metals in a pure hydrocarbon without resort to an external electric field.In addition,we calculated the spin-dependent transportation of the semiconducting ZCNSs with 12 and 20 zigzag chains,and found that they are 13% and 17% at the Fermi level,respectively,suggesting that ZCNS can be an effective spin filter.展开更多
Diameter- and chirality-dependent interactions between aromatic molecule-based nanotweezers and single-walled carbon nanotubes (SWNTs) are revealed by density functional theory calculations. We found that the threshol...Diameter- and chirality-dependent interactions between aromatic molecule-based nanotweezers and single-walled carbon nanotubes (SWNTs) are revealed by density functional theory calculations. We found that the threshold diameter of selected SWNTs is determined by the end-to-end distance of the nanotweezer. Large-diameter SWNTs are preferred by a nanotweezer with an obtuse folding angle, whereas small-diameter SWNTs are favored by a nanotweezer with an acute folding angle. The adsorption can be further stabilized by the orientational alignment of the hexagonal rings of the nanotweezer and the SWNT sidewall. Therefore, by taking advantage of the supramolecular recognition ability of the aromatic molecule-based nanotweezer, SWNTs can be enriched with both controllable diameter and chirality.展开更多
基金the National Natural Science Foundation of China(NSFC)(Grant Nos.10774003,10474123,10434010,90606023,and 20731160012)National 973 Projects(No.2007CB936200,Ministry of Science and Technology(MOST)of China)Program for New Century Excellent Talents in University of Ministry of Education(MOE)of China,the Grant-in-Aid for National Research Grid Initiative(NAREGI)Nanoscience Project from the Ministry of Education,Sports,Culture,Science and Technology(MEXT)of Japan,the Kurata Memorial Hitachi Science and Technology Foundation,and Nebraska Research Initiative(No.4132050400)of USA.
文摘A magnetic ground state is revealed for the first time in zigzag-edged carbon nanoscrolls(ZCNSs)from spin-unrestricted density functional theory calculations.Unlike their flat counterpart-zigzag-edged carbon nanoribbons,which are semiconductors with spin-degenerate electronic structure-ZCNSs show a variety of magnetic configurations,namely spin-selective semiconductors,metals,semimetals,quasi-half-metals,and half-metals.To the best of our knowledge,this is the first discovery of quasi-half-metals and half-metals in a pure hydrocarbon without resort to an external electric field.In addition,we calculated the spin-dependent transportation of the semiconducting ZCNSs with 12 and 20 zigzag chains,and found that they are 13% and 17% at the Fermi level,respectively,suggesting that ZCNS can be an effective spin filter.
基金This work was supported by the the National Natural Science Foundation of China(NSFC)(Nos.10774003,10474123,10434010,90626223,and 20731162012)the National Basic Research Program of China(973 Program)(Nos.2002CB613505 and 2007CB936200,MOST of China)+2 种基金the Program for New Century Excellent Talents in University of Ministry of Education of China,National Foundation for Fostering Talents of Basic Science(No.J0630311)and Nebraska Research Initiative of USA(No.4132050400)We thank R.M.Tromp and A.Afzali for helpful discussions of solvent effects.
文摘Diameter- and chirality-dependent interactions between aromatic molecule-based nanotweezers and single-walled carbon nanotubes (SWNTs) are revealed by density functional theory calculations. We found that the threshold diameter of selected SWNTs is determined by the end-to-end distance of the nanotweezer. Large-diameter SWNTs are preferred by a nanotweezer with an obtuse folding angle, whereas small-diameter SWNTs are favored by a nanotweezer with an acute folding angle. The adsorption can be further stabilized by the orientational alignment of the hexagonal rings of the nanotweezer and the SWNT sidewall. Therefore, by taking advantage of the supramolecular recognition ability of the aromatic molecule-based nanotweezer, SWNTs can be enriched with both controllable diameter and chirality.
