The size and the shape of non-reversal random-walking polymerchains near an impenetrable, non- interacting flat surface areinvestigated by means of Monte Carlo simulation on the simple cubiclattice. It was found that ...The size and the shape of non-reversal random-walking polymerchains near an impenetrable, non- interacting flat surface areinvestigated by means of Monte Carlo simulation on the simple cubiclattice. It was found that both size and shape are dependent on thenormal-to-surface distance z_0 of the first segment of chain. We findthat the size and shape of chains, characterized by mean squareradius of gyration and mean asphericity parameter respectively, show similar dependence on distance z_0.展开更多
The effect of Sb addition on the morphology of self-catalyzed InAsSb nanowires （NWs） has been systematically investigated. InAs NWs were grown by molecular beam epitaxy with and without antimony （Sb） flux. It is d...The effect of Sb addition on the morphology of self-catalyzed InAsSb nanowires （NWs） has been systematically investigated. InAs NWs were grown by molecular beam epitaxy with and without antimony （Sb） flux. It is demonstrated that trace amounts of Sb flux are capable of tuning the geometry of NWs, i.e., enhancing lateral growth and suppressing axial growth. We attribute this behavior to the surfactant effect of Sb which results in modifications to the kinetic and thermodynamic processes. A thermodynamic mechanism that accounts for Sb segregation in InAsSb NWs is also elucidated. This study opens a new route towards precisely controlled NW geometries by means of Sb addition.展开更多
The surface geometry, electronic structure, and magnetism of Eu@C60 monolayer absorbed on Ag(111) have been investigated within the framework of density functional theory. The Eu@C60 monolayer has been constructed on ...The surface geometry, electronic structure, and magnetism of Eu@C60 monolayer absorbed on Ag(111) have been investigated within the framework of density functional theory. The Eu@C60 monolayer has been constructed on Ag(111) substrate by one of the hexagon faces of C60 downward and its mirror plane face parallel to Ag(111). The Eu@C60 monolayer induces a recon- struction of the Ag(111) substrate and the perpendicular distance between the Eu@C60 and Ag(111) surface is 2.06 A, being shorter than that between C60 and Ag(lll) surface by 0.05A. There is no chemical bond formed between the Eu@C60 and Ag(111), and only 0.55e transferred from Ag(111) to Eu@C60. A large magnetic moment about 6.80/μB per unit cell is found for Eu@C60/Ag(111) system.展开更多
基金Supported by the National Natural Science Foundation of China (No. 20076038).
文摘The size and the shape of non-reversal random-walking polymerchains near an impenetrable, non- interacting flat surface areinvestigated by means of Monte Carlo simulation on the simple cubiclattice. It was found that both size and shape are dependent on thenormal-to-surface distance z_0 of the first segment of chain. We findthat the size and shape of chains, characterized by mean squareradius of gyration and mean asphericity parameter respectively, show similar dependence on distance z_0.
文摘The effect of Sb addition on the morphology of self-catalyzed InAsSb nanowires （NWs） has been systematically investigated. InAs NWs were grown by molecular beam epitaxy with and without antimony （Sb） flux. It is demonstrated that trace amounts of Sb flux are capable of tuning the geometry of NWs, i.e., enhancing lateral growth and suppressing axial growth. We attribute this behavior to the surfactant effect of Sb which results in modifications to the kinetic and thermodynamic processes. A thermodynamic mechanism that accounts for Sb segregation in InAsSb NWs is also elucidated. This study opens a new route towards precisely controlled NW geometries by means of Sb addition.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10874039 and 11147172)support from the National Basic Research Program of China (Grant No. 2011CB606401)
文摘The surface geometry, electronic structure, and magnetism of Eu@C60 monolayer absorbed on Ag(111) have been investigated within the framework of density functional theory. The Eu@C60 monolayer has been constructed on Ag(111) substrate by one of the hexagon faces of C60 downward and its mirror plane face parallel to Ag(111). The Eu@C60 monolayer induces a recon- struction of the Ag(111) substrate and the perpendicular distance between the Eu@C60 and Ag(111) surface is 2.06 A, being shorter than that between C60 and Ag(lll) surface by 0.05A. There is no chemical bond formed between the Eu@C60 and Ag(111), and only 0.55e transferred from Ag(111) to Eu@C60. A large magnetic moment about 6.80/μB per unit cell is found for Eu@C60/Ag(111) system.
