Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Cleveland State University

Series

2008

Discipline
Keyword
Publication
File Type

Articles 1 - 30 of 43

Full-Text Articles in Physical Sciences and Mathematics

Rainbows In The Grass. Ii. Arbitrary Diagonal Incidence, Charles L. Adler, James A. Lock, Richard W. Fleet Dec 2008

Rainbows In The Grass. Ii. Arbitrary Diagonal Incidence, Charles L. Adler, James A. Lock, Richard W. Fleet

Physics Faculty Publications

We consider external reflection rainbow caustic,,; due to the reflection of light from a pendant droplet where the light rays are at an arbitrary angle with respect to the horizontal. We compare this theory to observation of glare spots from, pendant drops on grass; we also consider the potential application of this theory to the determination of liquid surface tension. (C) 2008 Optical Society of America

Go to article

Scattering Of An Electromagnetic Plane Wave By A Luneburg Lens. I. Ray Theory, James A. Lock Dec 2008

Scattering Of An Electromagnetic Plane Wave By A Luneburg Lens. I. Ray Theory, James A. Lock

Physics Faculty Publications

For a plane wave incident on either a Luneburg lens or a modified Luneburg lens, the magnitude and phase of the transmitted electric field are calculated as a function of the scattering angle in the context of ray theory. It is found that the ray trajectory and the scattered intensity are not uniformly convergent in the vicinity of edge ray incidence on a Luneburg lens, which corresponds to the semiclassical phenomenon of orbiting. In addition, it is found that rays transmitted through a large-focal-length modified Luneburg lens participate in a far-zone rainbow, the details of which are exactly analytically soluble …

Go to article

Rainbows In The Grass. I. External Reflection Rainbows From Pendant Droplets, James A. Lock, Charles L. Adler, Richard W. Fleet Dec 2008

Rainbows In The Grass. I. External Reflection Rainbows From Pendant Droplets, James A. Lock, Charles L. Adler, Richard W. Fleet

Physics Faculty Publications

In the mid-morning on a sunny day one can sometimes see glare spots associated with uncolored "rainbow" (i.e., fold) caustics due to the sunlight reflected from the surface of dew or guttation drops. We show that these dewdrop reflection rainbows are due to places on the droplet (i.e., from an "inflection circle") where its Gaussian curvature becomes zero. We work out the theory of such caustics with horizontally incident light and present a comparison of the theory to measurements made in the laboratory. (C) 2008 Optical Society of America

Go to article

Scattering Of An Electromagnetic Plane Wave By A Luneburg Lens. Iii. Finely Stratified Sphere Model, James A. Lock Dec 2008

Scattering Of An Electromagnetic Plane Wave By A Luneburg Lens. Iii. Finely Stratified Sphere Model, James A. Lock

Physics Faculty Publications

The parallel iteration procedure for computing scattering by a multilayer sphere is described. The procedure uses a successive doubling strategy applied to four sets of multiple-scattering amplitudes, which is reminiscent of the fast Fourier transform (FFT) algorithm. The procedure is then used to calculate scattering of a plane wave by a modified Luneburg lens. The evolution of the transmission rainbow for the Luneburg lens parameter f > 1 into an orbiting ray for f = 1 and into a series of morphology-dependent resonances for f < 1 is studied, and various features of the scattered intensity as a function of scattering angle are commented on. It is found that some resonances are formed without the presence of an exterior centrifugal barrier to confine them. (C) 2008 Optical Society of America

Go to article

Scattering Of An Electromagnetic Plane Wave By A Luneburg Lens. Ii. Wave Theory, James A. Lock Dec 2008

Scattering Of An Electromagnetic Plane Wave By A Luneburg Lens. Ii. Wave Theory, James A. Lock

Physics Faculty Publications

The partial wave scattering and interior amplitudes for the interaction of an electromagnetic plane wave with a modified Luneburg lens are derived in terms of the exterior and interior radial functions of the scalar radiation potentials evaluated at the lens surface. A Debye series decomposition of these amplitudes is also performed and discussed. The effective potential inside the lens for the transverse electric polarization is qualitatively examined, and the approximate lens size parameters of morphology-dependent resonances are determined. Finally, the physical optics model is used to calculate wave scattering in the vicinity of the ray theory orbiting condition in order …

Go to article

Spectral Time Moment Analysis Of Microgel Deswelling: Effect Of The Heating Rate, Kiril A. Streletzky, John T. Mckenna Nov 2008

Spectral Time Moment Analysis Of Microgel Deswelling: Effect Of The Heating Rate, Kiril A. Streletzky, John T. Mckenna

Physics Faculty Publications

Microgel nanoparticles were synthesized in aqueous solutions of neutral polymer hydroxypropylcellulose (HPC) through the self-association of amphiphilic HPC molecules and the subsequent cross linking at room temperature. Dynamic Light Scattering was used to study the transport properties of HPC microgels below and above the volume phase transition. Highly nonexponential, multimodal microgel spectra were observed and successfully analyzed by spectral time moment analysis. This article expands earlier results and focuses on the effect of the heating rate on microgel deswelling. During the fast heating two identified microgel modes with apparent hydrodynamic radii (RH) of 25–30 nm and 400–650 nm collapse into …

Go to article

Turbulent Dispersion In Cloudy Boundary Layers, Remco A. Verzijlbergh, Harmen J.J. Jonker, Thijs Heus, J. Vilà-Guerau De Arellano Nov 2008

Turbulent Dispersion In Cloudy Boundary Layers, Remco A. Verzijlbergh, Harmen J.J. Jonker, Thijs Heus, J. Vilà-Guerau De Arellano

Physics Faculty Publications

Compared to dry boundary layers, dispersion in cloud-topped boundary layers has received less attention. In this LES based numerical study we investigate the dispersion of a passive tracer in the form of Lagrangian particles for four kinds of atmospheric boundary layers: 1) a dry convective boundary layer (for reference), 2) a "smoke" cloud boundary layer in which the turbulence is driven by radiative cooling, 3) a stratocumulus topped boundary layer and 4) a shallow cumulus topped boundary layer. We show that the dispersion characteristics of the smoke cloud boundary layer as well as the stratocumulus situation can be well understood …

Go to article

Genetic Markers Of Igg Influence The Outcome Of Infection With Hepatitis C Virus, Janardan P. Pandey, Aryan M. Namboodiri, Yuqun Luo, Yuping Wu, Robert C. Elston, David L. Thomas, Hugo R. Rosen, James J. Goedert Nov 2008

Genetic Markers Of Igg Influence The Outcome Of Infection With Hepatitis C Virus, Janardan P. Pandey, Aryan M. Namboodiri, Yuqun Luo, Yuping Wu, Robert C. Elston, David L. Thomas, Hugo R. Rosen, James J. Goedert

Mathematics and Statistics Faculty Publications

We examined the role that immunoglobulin GM and KM allotypes—genetic markers of γ and κ chains, respectively—play in the outcome of hepatitis C virus (HCV) infection in white Americans. A total of 119 persons who had cleared HCV and 111 with persistent HCV infection were genotyped for the presence of several GM and KM determinants. Persistent HCV infection was more than three times as likely (odds ratio, 3.50; P = .01) in subjects who were carriers of the GM3 allele than in those who were noncarriers. These results show that particular GM alleles may be important determinants of the outcome …

Go to article

2008 Scholars And Artists Bibliography, Rajshehkar G. Javalgi Dr., Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library Oct 2008

2008 Scholars And Artists Bibliography, Rajshehkar G. Javalgi Dr., Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library

Scholars and Artists Bibliographies

This bibliography was created for the annual Friends of the Michael Schwartz Library Scholars and Artists Reception, recognizing scholarly and creative achievements of Cleveland State University faculty, staff and emeriti. Dr. Rajshekhar Javalgi was the guest speaker.

Go to article

Npdes Storm Water Training: Program: Closing Activity Report, Daila Shimek Oct 2008

Npdes Storm Water Training: Program: Closing Activity Report, Daila Shimek

All Maxine Goodman Levin School of Urban Affairs Publications

This report discusses the outcome and evaluation of the training program conducted by the GLEFC and funded by the Ohio EPA’s Office of Environmental Education.

Go to article

The Matrices R And G Of Matrix Analytic Methods And The Time-Inhomogeneous Periodic Quasi-Birth-And-Death Process, Barbara H. Margolius Oct 2008

The Matrices R And G Of Matrix Analytic Methods And The Time-Inhomogeneous Periodic Quasi-Birth-And-Death Process, Barbara H. Margolius

Mathematics and Statistics Faculty Publications

We solve for the asymptotic periodic distribution of the continuous time quasi-birth-and-death process with time-varying periodic rates in terms of R^ and G^ matrix functions which are analogues of the R and G matrices of matrix analytic methods. We evaluate these QBDs numerically by solving for R^ numerically.

Go to article

Structure Of The Catalytic Trimer Of Methanococcus Jannaschii Aspartate Transcarbamoylase In An Orthorhombic Crystal Form, Jacqueline Vitali, Michael J. Colaneri Sep 2008

Structure Of The Catalytic Trimer Of Methanococcus Jannaschii Aspartate Transcarbamoylase In An Orthorhombic Crystal Form, Jacqueline Vitali, Michael J. Colaneri

Physics Faculty Publications

Crystals of the catalytic subunit of Methanococcus jannaschii aspartate transcarbamoylase in an orthorhombic crystal form contain four crystallographically independent trimers which associate in pairs to form stable staggered complexes that are similar to each other and to a previously determined monoclinic C2 form. Each subunit has a sulfate in the central channel. The catalytic subunits in these complexes show flexibility, with the elbow angles of the monomers differing by up to 7.4 degrees between crystal forms. Moreover, there is also flexibility in the relative orientation of the trimers around their threefold axis in the complexes, with a difference of 4 …

Go to article

Mixing In Shallow Cumulus Clouds Studied By Lagrangian Particle Tracking, Thijs Heus, Gertjan Van Dijk, Harmen J.J. Jonker, Harry E.A. Van Den Akker Aug 2008

Mixing In Shallow Cumulus Clouds Studied By Lagrangian Particle Tracking, Thijs Heus, Gertjan Van Dijk, Harmen J.J. Jonker, Harry E.A. Van Den Akker

Physics Faculty Publications

Mixing between shallow cumulus clouds and their environment is studied using large-eddy simulations. The origin of in-cloud air is studied by two distinct methods: 1) by analyzing conserved variable mixing diagrams (Paluch diagrams) and 2) by tracing back cloud-air parcels represented by massless Lagrangian particles that follow the flow. The obtained Paluch diagrams are found to be similar to many results in the literature, but the source of entrained air found by particle tracking deviates from the source inferred from the Paluch analysis. Whereas the classical Paluch analysis seems to provide some evidence for cloud-top mixing, particle tracking shows that …

Go to article

Palmated Antlers Of Moose May Serve As A Parabolic Reflector Of Sounds, George A. Bubenik, Peter G. Bubenik Aug 2008

Palmated Antlers Of Moose May Serve As A Parabolic Reflector Of Sounds, George A. Bubenik, Peter G. Bubenik

Mathematics and Statistics Faculty Publications

It has been postulated that the excellent sense of hearing in moose is mostly due to: (1) the large surface of the external ear, (2) better stereophony due to the large distance between ears, (3) independently movable, extremely adjustable pinna, and (4) the amplification of sounds reflected by the palms of the antlers. The last factor, possible reflection of sounds into pinna by the palm of the antlers, was tested in this study on a large antler trophy of Alaskan moose. The reception of a standard tone, broadcast from the frontally placed speaker, was recorded by a sound level meter …

Go to article

Radiation Torque Exerted On A Spheroid: Analytical Solution, Feng Xu, James A. Lock, Gérard Gouesbet, Cameron Tropea Jul 2008

Radiation Torque Exerted On A Spheroid: Analytical Solution, Feng Xu, James A. Lock, Gérard Gouesbet, Cameron Tropea

Physics Faculty Publications

As a companion work to our previous study [F. Xu, , Phys. Rev. E. 75, 026613 (2007)] on radiation force prediction for a homogeneous spheroid, we provide in this paper the analytical solution to the radiation torque exerted by an arbitrarily shaped beam on a spheroid, which can be prolate or oblate, transparent or absorbing. Calculations based upon this theoretical development are performed for both linearly and circularly polarized incident beams, and the results are compared to those of a sphere. Stable orientations of spheroids inside a linearly and a circularly polarized Gaussian beam are predicted. We analyze two physical …

Go to article

Criteria For Components Of A Function Space To Be Homotopy Equivalent, Gregory Lupton, Samuel Bruce Smith Jul 2008

Criteria For Components Of A Function Space To Be Homotopy Equivalent, Gregory Lupton, Samuel Bruce Smith

Mathematics and Statistics Faculty Publications

We give a general method that may be effectively applied to the question of whether two components of a function space map(X, Y) have the same homotopy type. We describe certain group-like actions on map(X, Y). Our basic results assert that if maps f, g: X → Y are in the same orbit under such an action, then the components of map(X, Y) that contain f and g have the same homotopy type.

Go to article

Spectroscopy Is Applied Quantum Mechanics. Part 4: Ideal Systems, David W. Ball Jun 2008

Spectroscopy Is Applied Quantum Mechanics. Part 4: Ideal Systems, David W. Ball

Chemistry Faculty Publications

The article features the last and fourth part of the lecture series about the application of quantum mechanics to spectroscopy. It examines ideal systems with wave functions that can be derived from the Schroedinger equation. It likewise follows discourse for failings of classical mechanics, the quantum hypothesis, and the emergence of a new theory called quantum mechanics.

Go to article

The Propagation Of Non-Lefschetz Type, The Gottlieb Group And Related Questions, John Oprea May 2008

The Propagation Of Non-Lefschetz Type, The Gottlieb Group And Related Questions, John Oprea

Mathematics and Statistics Faculty Publications

This is a brief note which indicates how the property of being non-Lefschetz may be propagated by equivariant symplectic maps. We also discuss some questions related to the Gottlieb group and nilpotency of symplectic manifolds.

Go to article

Spectral Time Moment Analysis Of Microgel Structure And Dynamics, Kiril A. Streletzky, John T. Mckenna, Rami Mohieddine Apr 2008

Spectral Time Moment Analysis Of Microgel Structure And Dynamics, Kiril A. Streletzky, John T. Mckenna, Rami Mohieddine

Physics Faculty Publications

The structure and dynamics of crosslinked nanoparticles (microgels) made out of hydroxypropylcellulose (HPC) polymer chains were studied using dynamic light scattering spectroscopy. The microgel light scattering spectra were found to be highly nonexponential requiring a spectral time moment analysis in which the spectra were fit to a sum of stretched exponentials. Each term offers three parameters for analysis and represents a single spectral mode. At room temperature microgel spectra reveal three modes. Two faster modes are almost diffusive and correspond to apparent sizes of 25 and 450–650 nm. The slowest mode is independent of scattering angle and is reminiscent of …

Go to article

Spectroscopy Is Applied Quantum Mechanics. Part 3: Introduction To Quantum Mechanics, David W. Ball Apr 2008

Spectroscopy Is Applied Quantum Mechanics. Part 3: Introduction To Quantum Mechanics, David W. Ball

Chemistry Faculty Publications

The article discusses the pioneering work of Erwin Schrödinger on wave mechanics that forms the basis of modern understanding in subatomic behavior. Schrödinger introduced a second-order differential equation that had to be solved to explain the nature of the hydrogen atom. He also demonstrated that the matrix mechanics of Heisenberg and Born were mathematically equivalent and developed the concept of perturbation theory to explain the Stark effect.

Go to article

Investigation Of Magnetic Interactions In Large Arrays Of Magnetic Nanowires, Petru S. Fodor, G. M. Tsoi, L. W. Wenger Apr 2008

Investigation Of Magnetic Interactions In Large Arrays Of Magnetic Nanowires, Petru S. Fodor, G. M. Tsoi, L. W. Wenger

Physics Faculty Publications

The magnetic interactions in large arrays of ordered magnetic nanowires with 12-48 nm diameter and 55-95 nm spacing were investigated using modified Henkel plots. The measurements for nanowire arrays ac demagnetized with the field applied parallel to the nanowire axis (the easy magnetization axis) indicate that the dominant interaction during the switching process is the magnetostatic coupling between the nanowires. Nevertheless, while the strength of the magnetostatic interactions increases with the magnetic moment associated with the nanowires, the increase is not linear with respect to the volume of the nanowires. Moreover, the dependence of the remanence curves on the field …

Go to article

A Refined View Of Vertical Mass Transport By Cumulus Convection, Harmen J.J. Jonker, Thijs Heus, Peter P. Sullivan Apr 2008

A Refined View Of Vertical Mass Transport By Cumulus Convection, Harmen J.J. Jonker, Thijs Heus, Peter P. Sullivan

Physics Faculty Publications

The purpose of this letter is to show that the traditional view of transport by shallow cumulus clouds needs important refinement. On the basis of a straightforward geometrical analysis of Large Eddy Simulation results of shallow cumulus clouds, we conclude (1) that the upward mass transport by clouds is strongly dominated by regions close to the edge of clouds rather than by the core region of clouds and (2) that the downward mass transport is dominated by processes just outside the cloud. The latter finding contradicts the accepted view of a uniformly descending dry environment. We therefore advocate a refined …

Go to article

Two Classes Of Time-Inhomogeneous Markov Chains: Analysis Of The Periodic Case, Attahiru Sule Alfa, Barbara Haas Margolius Apr 2008

Two Classes Of Time-Inhomogeneous Markov Chains: Analysis Of The Periodic Case, Attahiru Sule Alfa, Barbara Haas Margolius

Mathematics and Statistics Faculty Publications

We consider the M/G/1 and GI/M/1 types of Markov chains for which their one step transitions depend on the times of the transitions. These types of Markov chains are encountered in several stochastic models, including queueing systems, dams, inventory systems, insurance risk models, etc. We show that for the cases when the time parameters are periodic the systems can be analyzed using some extensions of known results in the matrix-analytic methods literature. We have limited our examples to those relating to queueing systems to allow us a focus. An example application of the model to a real life problem is …

Go to article

Elastically Induced Coexistence Of Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Chris Pearson, Joanna Mirecki Millunchick Mar 2008

Elastically Induced Coexistence Of Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Chris Pearson, Joanna Mirecki Millunchick

Physics Faculty Publications

Scanning tunneling microscopy of Sb-capped GaAs shows the coexistence of different surface reconstructions. The majority of the surface consists of an α2(2×4) reconstruction typically observed for GaAs(001) surfaces. At step edges, an α(4×3) reconstruction, common for GaSb(001), is observed. We argue that strain couples the surface reconstruction to the film morphology. Density functional theory calculations show that the (2×4) reconstruction is stabilized in GaSb films when the lattice parameter is constrained to that of GaAs, as happens in the middle of a terrace, while the (4×3) reconstruction is stabilized when the lattice parameter is allowed to relax toward that of …

Go to article

4-Hydroxyphenylretinamide (4hpr) Derivatives Regulate Aromatase Activity And Expression In Breast Cancer Cells, Bin Su, Serena M. Mershon, Laura A. Stonerock, Robert W. Curley Jr., Robert W. Brueggemeier Mar 2008

4-Hydroxyphenylretinamide (4hpr) Derivatives Regulate Aromatase Activity And Expression In Breast Cancer Cells, Bin Su, Serena M. Mershon, Laura A. Stonerock, Robert W. Curley Jr., Robert W. Brueggemeier

Chemistry Faculty Publications

Recent studies exhibit that 4-hydroxyphenylretinamide (4HPR) decreases aromatase activity in breast and placental cells. The effect of synthetic 4HPR analogs on aromatase and expression was examined in three breast cancer cell lines. Most derivatives did not decrease cellular aromatase activity. Two of the analogs even stimulated aromatase activity at the transcriptional level. Only one derivative significantly decreased aromatase in all three breast cancer cell lines and also suppressed CYP19 gene expression in one of the cell line. Placental microsomal aromatase assay rule out the possibility that this compound directly inhibits the aromatase enzyme. A non-genomic mechanism in suppression of cellular …

Go to article

A Facile And Efficient Synthesis Of Some (6e)-Hydroximino-4-En-3-One Steroids, Steroidal Oximes From Cinachyrella Spp. Sponges, Jianguo Cui, Liliang Huang, Lei Fan, Aimin Zhou Mar 2008

A Facile And Efficient Synthesis Of Some (6e)-Hydroximino-4-En-3-One Steroids, Steroidal Oximes From Cinachyrella Spp. Sponges, Jianguo Cui, Liliang Huang, Lei Fan, Aimin Zhou

Chemistry Faculty Publications

Using β-sitosterol as a starting material, (6E)-hydroximino-24-ethylcholest-4-en-3-one (1), a natural steroidal oxime from Cinachyrella alloclada and C. apion, was synthesized in four steps with a high overall yield. First, β-sitosterol (5a) is transformed into the corresponding 24-ethylcholest-4-en-3,6-dione (6a) via oxidation with pyridinium chlorochromate (PCC). Selective reduction of 6a by NaBH4 in the presence of CoCl2 gives 24-ethylcholest- 4-en-3β-ol-6-one (7a). The reaction of 7a with hydroxylamine hydrochloride offers the oxime 8a and the oxidation of 8a by Jones reagent gives the target steroid 1. (6E)-Hydroximinocholest-4-en-3-one (2) and (6E)-hydroximino-24-ethylcholest-4,22-dien-3-one (4) were synthesized by a similar method. The cytotoxicity of the synthesized compounds …

Go to article

Determination Of Endocannabinoid Receptor Antagonist Sr141716 (Rimonabant) In Plasma By Liquid Chromatograph Tandem Mass Spectrometry, Melissa Mcculloch, Xiang Zhou, Yan Xu, Steve Brunell, Linda Spear Mar 2008

Determination Of Endocannabinoid Receptor Antagonist Sr141716 (Rimonabant) In Plasma By Liquid Chromatograph Tandem Mass Spectrometry, Melissa Mcculloch, Xiang Zhou, Yan Xu, Steve Brunell, Linda Spear

Chemistry Faculty Publications

SR141716 (rimonabant) is an endocannabinoid receptor antagonist. Endocannabinoids are a class of chemicals that affect neurotransmission via G-protein coupled CB1 (brain) and CB2 (peripheral tissue) receptors. Numerous animal studies have shown that SR141716 binds with the CB1 receptor in the brain, resulting in several biological consequences including reduced alcohol intake and reward as well as reduced food consumption. In this work, an analytical method based on liquid chromatography and electrospray ionization tandem mass spectrometry (LC–ESI-MS/MS) has been developed and validated for the quantitative measurement of SR141716 in both human and rat plasma to support the investigation of this compound. A …

Go to article

Dipole In A Magnetic Field, Work, And Quantum Spin, Robert J. Deissler Mar 2008

Dipole In A Magnetic Field, Work, And Quantum Spin, Robert J. Deissler

Physics Faculty Publications

The behavior of an atom in a nonuniform magnetic field is analyzed, as well as the motion of a classical magnetic dipole (a spinning charged ball) and a rotating charged ring. For the atom it is shown that, while the magnetic field does no work on the electron-orbital contribution to the magnetic moment (the source of translational kinetic energy being the internal energy of the atom), whether or not it does work on the electron- spin contribution to the magnetic moment depends on whether the electron has an intrinsic rotational kinetic energy associated with its spin. A rotational kinetic energy …

Go to article

Subsiding Shells Around Shallow Cumulus Clouds, Thijs Heus, Harmen J.J. Jonker Mar 2008

Subsiding Shells Around Shallow Cumulus Clouds, Thijs Heus, Harmen J.J. Jonker

Physics Faculty Publications

In this study large-eddy simulations (LES) are used to gain more knowledge on the shell of subsiding air that is frequently observed around cumulus clouds. First, a detailed comparison between observational and numerical results is presented to better validate LES as a tool for studies of microscale phenomena. It is found that horizontal cloud profiles of vertical velocity, humidity, and temperature are in good agreement with observations. They show features similar to the observations, including the presence of the shell of descending air around the cloud. Second, the availability of the complete 3D dataset in LES has been exploited to …

Go to article

Atomic Size Mismatch Strain Induced Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Anton Van Der Ven, Joanna Mirecki Millunchick Feb 2008

Atomic Size Mismatch Strain Induced Surface Reconstructions, Jessica E. Bickel, Normand A. Modine, Anton Van Der Ven, Joanna Mirecki Millunchick

Physics Faculty Publications

The effects of lattice mismatch strain and atomic size mismatch strain on surface reconstructions are analyzed using density functional theory. These calculations demonstrate the importance of an explicit treatment of alloying when calculating the energies of alloyed surface reconstructions. Lattice mismatch strain has little impact on surface dimer ordering for the α2(2×4) reconstruction of GaAs alloyed with In. However, atomic size mismatch strain induces the surface In atoms to preferentially alternate position, which, in turn, induces an alternating configuration of the surface anion dimers. These results agree well with experimental data for α2(2×4) domains in InGaAs∕GaAs surfaces.

Go to article

Next Last