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Proceedings of the 4th International Conference onNanostructures (ICNS4)12-14 March 2012, Kish Island, I.R. Iran

Abstract Book | INST| Sharif University of Technology | 177

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First-principles calculations are performed to investigate the electronic properties and band alignment of Sb/(Ga, In) junction in the zinc-blend(zb)-CrSb/Ga 0.87In0.13 As (001) heterojunction. In our previous article,we considered only Cr/As and Sb/Ga junction of this heterojunction;

but to be sure about preserving half-metallicity at this heterojunction,we should study the Sb/(Ga, In) junction that is especially differentfrom the previous ones: It contains Indium atoms that have states of energy that are completely different from Ga atoms and therefore canchange the results of calculations on Sb/Ga junction. The results of Sb/(Ga, In) junction con rm that half-metallicity persists at the interfaceand band alignment imply that the majority spin can be injected intoGa0.87In0.13As without being ipped to the conduction bands of theminority spin. Consequently, the CrSb/Ga 0.87In0.13As heterojunction can

be potentially useful in the eld of spintronics. According to our resultson the zb-CrSb/Ga 0.87In0.13As (001) heterojunction, we concluded thatif the CrSb/(Ga, In)As (001) heterojunction is made in a manner thatits interface be Cr/As (that is possible with epitaxial growth), it would

be so suitable for spintronic devices in nano-electronics.

Keywords: Half-metal; Spintronic; Nano-electronics; Heterojunction;Density functional theory

Z. Soltani a*, M. Moradi b a Department of Physics, Shiraz Branch, Islamic Azad University, Shiraz, Iranb Department of Physics, Shiraz University, Shiraz, 71454, Iran*zsoltany@yahoo.com

Half-Metallicity at the zinc-blend (zb)-CrSb/Ga 0.87 In0.13 As Heterojunc on; Sb/(Ga, In) (001) Junc on

we study certain structural and transport properties of a two dimensionalliquid crystal in a nano-layer composed of hard ellipses by Monte Carlosimulation. We measure properties such as angular number density,order parameter, rotational and translational mean square displacement(MSD) near a monolayer both in laboratory and body frame of ellipses.The result shows that the effect of the existence of the walls on themolecular uid motion and their structure, especially near the walls,is signi cant.

Keywords: Nano-layer; Hard Ellipse; Monte Carlo

S. Davatolhagh*, S. ForoozanDepartment of Physics, College of Sciences Shiraz University, Shiraz,71454, Iran*Davatolhagh@susc.ac.ir

Monte Carlo Simula on of a Con ned Two DimensionalLiquid Crystal Nano-layer

Water inside carbon nanotubes as an example of nano-con ned water has gained a noticeable attention, in both theoretical and appliedaspects. Molecular simulation has played a major role in the studies inthis eld. Here we present a Monte Carlo simulation of water insidecarbon nanotubes with different radii. The simulation results show thatthe change in the con guration of water molecules inside the carbonnanotube causes noticeable changes in the physical properties of thissystem. The effect of density on the con guration of water inside thecarbon nanotubes is studied by calculating radial and axial pressurecomponents and the con gurational energy of water molecules.

Keywords: Water; Carbon nanotubes; Monte Carlo; Con gurations

M. Sadeghi a, G. A. Parsafar a, b * a Institute for Nanoscience and Nanotechnology (INST), Sharif University of Technology, Tehran, Iran.b Department of Chemistry, Sharif University of Technology, Tehran, Iran.*Parsafar@sharif.edu

Density-dependent Con gura ons of Water inside CarbonNanotubes

The structural, electronic and magnetic properties of (8, 0) and (8, 8)carbon nanotubes (CNT) in the presence of transition metal atomicchains (Fe, Ni, Co) have been studied by the rst principles densityfunctional theory. Our results show that the spin polarization isdepended on some parameters such as radii of nanotubes and typesof transition metal chains. The magnetic moment of atomic chainsdecreases by increasing the hybridization between 3d orbital of transition metal and 2 s and 2 p orbitals of carbon nanotubes.

Keywords: Spin polarization; CNT; Magnetic moment; Transition metal

B. Ghaderi a*, A. A. Shokri a, b, c a Department of Physics, Islamic Azad University North Tehran branch,Tehran, Iranb Department of Physics, Payame Noor University (PNU), 19395-4697, Iranc Computational Physical Sciences Research Laboratory, Department of Nano-Science, Institute for studies in theoretical Physics and Mathematics(IPM), Tehran, 19395-5531, Iran*bahareghaderi90@yahoo.com

Electronic and Magne c Properies of Single Transi onMetal (Fe, Co and Ni) Atomic Chains Encapsulated inCarbon Nanotubes

a Department of Physics, Payamenour University, Tehran, Iranb Institute for Nanotechnology and Advanced Materials, Materials and En-ergy Research Canter, Karaj, Iran*maryamroozbehi@yahoo.com

We have done a comparative study on theoretical model and experimentalresults of synthesized nanowires grown by the vapor-liquid-solid(VLS) mechanism during chemical vapour transport and condensation(TCRVTD) process. The dependence of length-diameter of nanowire hasshown the conventional adsorption-induced model, the diffusion-inducedmodel, and the model of nucleation-mediated for growing on the liquid-solid interface. In particular, it is shown that the length-diameter curves of nanowires have been converted from decreasing to increasing behaviour at a certain critical diameter. In addition, experimental results are in goodagreement with the theoretical predictions.

Keywords: Vapour-liquid-solid (VLS); Length-diameter dependence