Surface Segregation Maps Derived from Tight-Binding Ising Model

2011 ◽  
Vol 172-174 ◽  
pp. 1008-1015 ◽  
Author(s):  
Jean Marc Roussel ◽  
Guy Tréglia ◽  
Bernard Legrand
Keyword(s):  
Experimental Data ◽  
Electronic Structure ◽  
Ising Model ◽  
Surface Energy ◽  
Surface Segregation ◽  
Tight Binding ◽  
Electronic Structure Calculations ◽  
Matrix Elements ◽  
Metal Element ◽  
Structure Calculations

Surface segregation in transition metals can be analysed within a generalised Ising model,derived from Tight-Binding electronic structure calculations, which identifies three driving forces:the difference in surface energy and atomic volume between the two components and their tendencyto order or phase separate in the bulk. Using this ”three effects” rule, we present here general mapswhich predict the tendency of the solute metal element to segregate (or not) at the surface of a metalmatrix, for the 702 solute/matrix systems that can be formed with transition metal elements. Ourpredictions compare fairly well to the existing ab initio calculations and experimental data availableon these systems. The few exceptions, which mainly concern given matrix elements are discussed indetails.

Third Neighbor Analytic Tight-Binding Solutions for Electronic Structure of Carbon Nanosystems

2010 ◽  
Vol 659 ◽  
pp. 197-202
Author(s):  
István László
Keyword(s):  
Electronic Structure ◽  
Tight Binding ◽  
Electronic Structure Calculations ◽  
Diagonal Matrix ◽  
Graphene Sheets ◽  
Matrix Elements ◽  
Structure Calculations

Third neighbor analytic tight-binding formulae were obtained for graphene sheets and nanotubes. After fitting the corresponding of-diagonal matrix elements can be used in numerical electronic structure calculations of nanotubes and corrugated graphene.

Monte Carlo Simulations of Surface Segregation in Cu Ni Alloys

1992 ◽  
Vol 291 ◽  
Author(s):  
A. Pasturel ◽  
V. Drchal ◽  
J. Kudrnovsky ◽  
P. Weinberger
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Surface Segregation ◽  
Tight Binding ◽  
Electronic Structure Calculations ◽  
Orbital Method ◽  
Ni Alloys ◽  
Composition Profiles ◽  
Structure Calculations

ABSTRACTA new method coupling electronic structure calculations with Monte Carlo simulations has been developed to determine surface compositions in Cu-Ni alloys. The calculations are based on an effective Ising model with parameters as defined within the framework of the Generalized Perturbation Method (GPM) and as calculated by means of the tight-binding version of the linear muffin-tin orbital method. The composition profiles are obtained for the fcc(OOl) surface for three bulk compositions, namely Cu75Ni25, Cu50Ni50, and Cu25Ni75 and compared with available experimental data.

ELECTRONIC STRUCTURE CALCULATIONS FOR MoSe2 USING EXTENDED HUCKEL TIGHT-BINDING METHOD

2004 ◽  
Vol 18 (01) ◽  
pp. 35-44 ◽  
Author(s):  
DONALD H. GALVAN
Keyword(s):  
Electronic Structure ◽  
Density Of States ◽  
Population Analysis ◽  
Tight Binding ◽  
Electronic Structure Calculations ◽  
Total Density ◽  
Mulliken Population Analysis ◽  
Energy Bands ◽  
Mulliken Population ◽  
Structure Calculations

To gain insight into the electronic properties of MoSe 2 (molybdenum selenide, also known as drysdallite), electronic structure calculations, total and projected density of states, crystal orbital overlap population and Mulliken population analysis were performed. The calculated energy bands depict a semiconductor behavior with a direct gap (at K) of 0.91 eV and an indirect gap (from Γ to K) of 3.6 eV, respectively. Total and projected density of states provided information about the contribution from each orbital of each atom to the total density of states. Moreover, the bonding strength between some atoms within the unit cell was obtained. Mulliken population analysis corroborates the electron filling of the Mo dz2 orbitals in agreement with another experimental and theoretical results.

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