Half-Metallic Silicon Nanowires: Multiple Surface Dangling Bonds and Nonmagnetic Doping

A first-principles systematic study of GaAs nanowires

In this paper we present a detailed analysis of the atomic and electronic structure of GaAs nanowires using first-principles pseudopotential calculations. We consider six different types of nanowires with different diameters all grown along [111] direction and reveal interesting trends between cohesive energy and nanowire type with varying diameters. Generally, the average cohesive energy of nanowires with wurtzite stacking is higher than those with zinc blende stacking for small diameters. We found that most of the bare nanowires considered here are semiconducting and continue to be semicondu…

Ab-initio study of the stability and electronic properties of wurtzite and zinc-blende BeS nanowires

In this work we study the structural stability and electronic properties of the Beryllium sulphide nanowires (NWs) in both zinc blende (ZB) and wurtzite (WZ) phases with triangle and hexagonal cross section, using first principle calculations within plane-wave pseudopotential method. A phenomenological model is used to explain the role of dangling bonds in the stability of the NWs. In contrast to the bulk phase, ZB-NWs with diameter less than 133.3 (angstrom) are found to be less favorable over WZ-NWs, in which the surface dangling bonds (DBs) on the NW facets play an important role to stabili…

通过表面钝化调控硅纳米线的热导率

Tuning the thermal conductivity of silicon nanowires by surface passivation

本研究通过大规模分子动力学模拟，提出以表面过剩能为指导用氢/氧钝化硅纳米线悬挂键的方法，实现了通过表面覆盖浓度调控其热导率，并揭示了刚度变化的调控机制。

Electronic and Magnetic Properties of Mn doped Ge Nanowires

Using {\it ab initio} total energy density-functional theory calculations, we investigate the electronic, structural and magnetic properties of Manganese doped Germanium nanowires. The nanowires have been constructed along the [110] direction and the dangling bonds on the surface have been saturated by hydrogen atoms. We observed that the Mn has lower formation energy at the center of the wire when compared to regions close to the surface. The Mn-Mn coupling has lower energy for a high-spin configuration except when they are first nearest neighbors. These results show that Ge:Mn nanowires are …

Ballistic Anisotropic Magnetoresistance in Core Shell Nanowires and Rolled-up Nanotubes

In ferromagnetic nanostructures, the ballistic anisotropic magnetoresistance (BAMR) is a change in the ballistic conductance with the direction of magnetization due to spin-orbit interaction. Very recently, a directional dependent ballistic conductance has been predicted to occur in a number of newly synthesized nonmagnetic semiconducting nanostructures subject to externally applied magnetic fields, without necessitating spin-orbit coupling. In this article, we review past works on the prediction of this BAMR effect in core-shell nanowires and rolled-up nanotubes. This is complemented by new r…

Electronic and optical properties of Mn impurities in ultra-thin ZnO nanowires: insights from density-functional theory

In this work we have employed density-functional theory with hybrid functionals to investigate the atomic and electronic structure of bare and hydrogenated Mn doped ZnO nanowires with small diameter. We determine changes in magnetic and electronic structure of Mn-doped ZnO nanowires due to surface effects, such as hydrogen adsorption on the surface, presence of oxygen vacancies and dangling bonds. In the absence of passivation on the nanowire surface, the manganese atoms segregate to the surface, whereas under hydrogen adsorption the incorporation of Mn is energetically more favourable at inne…