Quantum-well and tight-binding analyses of spin-polarized photoemission from Ag/Fe(001) overlayers

1994 ◽  
Vol 49 (1) ◽  
pp. 332-338 ◽  
Author(s):  
N. V. Smith ◽  
N. B. Brookes ◽  
Y. Chang ◽  
P. D. Johnson
Keyword(s):  
Quantum Well ◽  
Tight Binding ◽  
Spin Polarized

Spin Polarized Photoemission Studies of Quantum well States in Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
P.D. Johnson ◽  
N.B. Brookes ◽  
Y. Chang ◽  
K. Garrison
Keyword(s):  
Thin Films ◽  
Electronic Structure ◽  
Quantum Well ◽  
Noble Metals ◽  
Tight Binding ◽  
Binding Energies ◽  
Cu Films ◽  
Minority Spin ◽  
Spin Polarized ◽  
Quantum Well States

ABSTRACTSpin polarized photoemission is used to study the electronic structure of noble metals deposited on ferromagnetic substrates. Studies of Ag deposited on an Fe (001) substrate reveal a series of minority spin interface or quantum well states with binding energies dependent on the thickness of the silver. Similar behavior is observed for Cu films deposited on a fee Co (001) substrate. Tight-binding Modeling reproduces many of the observations and shows that hybridization of the sp-bands with the noble metal d-bands cannot be ignored.

Zero Valley Splitting at Zero Magnetic Field for Strained Si/SiGe Quantum Wells

2007 ◽  
Vol 1017 ◽  
Author(s):  
Seungwon Lee ◽  
Paul von Allmen
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Conduction Band ◽  
Brillouin Zone ◽  
Tilt Angle ◽  
Tight Binding ◽  
Direct Consequence ◽  
Zero Magnetic Field ◽  
Strained Si ◽  
Valley Splitting

AbstractThe electronic structure for a strained silicon quantum well grown on a tilted SiGe substrate is calculated using an empirical tight-binding method. For a zero substrate tilt angle the two lowest minima of the conduction band define a non-zero valley splitting at the center of the Brillouin zone. A finite tilt angle for the substrate results in displacing the two lowest conduction band minima to finite k0 and -k0 in the Brillouin zone with equal energy. The vanishing of the valley splitting for quantum wells grown on tilted substrates is found to be a direct consequence of the periodicity of the steps at the interfaces between the quantum well and the buffer materials.

scholarly journals Coarse-grained tight-binding models

2021 ◽  
Author(s):  
Tianxiang Liu ◽  
Li Mao ◽  
Mats-Erik Pistol ◽  
Craig Pryor
Keyword(s):  
Quantum Well ◽  
Computing Time ◽  
Numerical Test ◽  
Tight Binding ◽  
Computation Time ◽  
Coarse Grained ◽  
Weakly Bound ◽  
Trade Offs ◽  
Full Calculation ◽  
Binding Models

Abstract Calculating the electronic structure of systems involving very different length scales presents a challenge. Empirical atomistic descriptions such as pseudopotentials or tight-binding models allow one to calculate the effects of atomic placements, but the computational burden increases rapidly with the size of the system, limiting the ability to treat weakly bound extended electronic states. Here we propose a new method to connect atomistic and quasi-continuous models, thus speeding up tight-binding calculations for large systems. We divide a structure into blocks consisting of several unit cells which we diagonalize individually. We then construct a tight-binding Hamiltonian for the full structure using a truncated basis for the blocks, ignoring states having large energy eigenvalues and retaining states with an energy close to the band edge energies. A numerical test using a GaAs/AlAs quantum well shows the computation time can be decreased to less than 5% of the full calculation with errors of less than 1%. We give data for the trade-offs between computing time and loss of accuracy. We also tested calculations of the density of states for a GaAs/AlAs quantum well and find a ten times speedup without much loss in accuracy.

MAGNETIC PROPERTIES OF ICOSAHEDRAL COPPER-COATED COBALT CLUSTERS

2004 ◽  
Vol 11 (01) ◽  
pp. 15-20 ◽  
Author(s):  
BAOLIN WANG ◽  
XIAOSHUANG CHEN ◽  
GUIBIN CHEN ◽  
GUANGHOU WANG ◽  
JIJUN ZHAO
Keyword(s):  
Genetic Algorithm ◽  
Magnetic Properties ◽  
Magnetic Moment ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Significant Modification ◽  
Binding Model ◽  
Model Hamiltonian ◽  
Spin Polarized ◽  
Structural And Magnetic Properties

The structural and magnetic properties of Cu -coated Co clusters are investigated with empirical genetic algorithm simulation and a spin-polarized spd tight-binding model Hamiltonian. In some specific stoichiometric compositions, icosahedral Co n (n=1, 2, 4, 7, 13, 19, 55) clusters perfectly coated with A Cu monolayer or dual layer are obtained. The outer Cu layers lead to significant modification of the magnetic moment of the Co core, depending on the structure and thickness of the Cu layers. The interaction between Cu and Co atoms induces a nonzero magnetic moment for Cu atoms.

Sign in / Sign up

Export Citation Format

Share Document