Factbites
 Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Electron gas


Related Topics

In the News (Tue 21 May 19)

  
  Electron gas grid semiconductor radiation detectors - US Patent 6344650   (Site not responding. Last check: 2007-10-17)
Since the electrons move toward the anode while the holes move away from the anode toward the cathode, due to their polarities, the signal on the anode will be dominated by the motion of the electrons.
Since electron trapping does occur in the detector, this non-uniformity of the electric field results in variation of the signal strength with the position of the x-ray and gamma-ray absorption event, and hence in loss of the energy resolution.
The present invention is an electron gas grid semiconductor radiation detector which employs doping of the semiconductor and variation of the semiconductor detector material to form a two-dimensional electron gas and to allow transistor action within the radiation detector.
www.patentstorm.us /patents/6344650.html   (5191 words)

  
 Gas electron diffraction - Wikipedia, the free encyclopedia
Gas electron diffraction (GED) is one of the applications of electron diffraction techniques.
The geometrical structure of molecules can be obtained directly from the observed electron diffraction pattern by using this method.
The total scattering intensity is given as a function of the momentum transfer, which is defined as the difference between the wave vector of the incident electron beam and that of the scattered electron beam and has the reciprocal dimension of length.
en.wikipedia.org /wiki/Gas_electron_diffraction   (217 words)

  
 Subsurface Charge Accumulation Imaging Home
The tip sensed the motions of single electrons entering or leaving the bubble in response to changes in the local 2D electrostatic potential.
As a result, a bubble of enhanced electron density forms underneath the tip and is dragged inside the 2DEG as the tip is scanned above the sample surface.
Electrons may tunnel across the strip in response to changes the local electrostatic potential of the 2DEG.
electron.mit.edu /imaging/stm   (439 words)

  
 The Uniform Electron Gas
82], all of which used the uniform electron gas as their model.
The uniform electron gas is defined as a large number of electrons N in a cube of volume V, throughout which there is a uniform spread of positive charge sufficient to make the system neutral.
The uniform electron gas is obviously a better reference system for exchange energies than it is for correlation energies.
www-theor.ch.cam.ac.uk /people/ross/thesis/node36.html   (303 words)

  
 Electron gas   (Site not responding. Last check: 2007-10-17)
A major application of the NCSA/Physics Quantum Simulation Group is the the electron gas (also known as the one component plasma, or jellium) with Path Integral, Variational and Diffusion Monte Carlo.
Kwon, Y., Ceperley, D. and Martin, R. "Quantum Monte Carlo calculation of the Fermi Liquid parameters in the two-dimensional electron gas", Phys.
Senatore, G., S. Moroni, and D. Ceperley "The Local Field of the Electron Gas" in proceedings of the (Binz Germany) International Conference on the Physics of Strongly Coupled Plasmas, eds.
archive.ncsa.uiuc.edu /Science/CMP/papers/egas.html   (569 words)

  
 The Homogeneous Electron Gas
The homogeneous electron gas is a widely used model in quantum many-particle physics.
The electron gas is most commonly used as a first approximation of metals where the the valence electrons are weakly bound to the ionic cores.
The homogeneous electron gas provides, in fact, the simplest model in which such non-trivial magnetic structures and electron localization can be obtained just by varying one parameter, namely the electronic density.
compphys.ucc.ie /est/thesis/node30.html   (248 words)

  
 Gas-Phase Ion Thermochemistry
That is, the electron affinity is equal to the energy difference between the enthalpy of formation of a neutral species and the enthalpy of formation of the negative ion of the same structure.
Since the electron transfer occurs in a long-lived collision complex which endures for many vibrational periods, the ionic configuration corresponding to the equilibrium geometry of the ion (the geometry corresponding to the adiabatic transition) is accessed.
However, strictly speaking, ionization energies, appearance energies, and electron affinities are quantities which correspond to processes occurring at 0 K. To correctly derive enthalpies of formation of ions from these kinds of data requires explicit treatment of the differences in thermochemical values at 0 K and at higher temperatures.
webbook.nist.gov /chemistry/ion   (14162 words)

  
 An Electron Runs through It: Science News Online, Dec. 18, 2004   (Site not responding. Last check: 2007-10-17)
Such electron behaviors "could be gremlins in future devices," adds Stanford University physicist Mark A. Topinka, "or maybe they could be exploited." Whether they prove detrimental or valuable may depend on what new forms transistors and other electronic devices take as chip makers shrink them ever smaller.
When electrons are confined to cold, cramped quarters, as two-dimensional electron gases in chilled semiconductor stacks are, their quantum natures loom large.
A 163-centimeter-by-122-cm print of one of his electron branching patterns hangs in the great rotunda of the National Academy of Sciences in Washington, D.C. Shows of his images have been presented this year at the Exposition Center of the University of Montreal and the Lawrence Hall of Science at the University of California, Berkeley.
www.sciencenews.org /articles/20041218/bob9.asp   (1956 words)

  
 Electronic stopping power of protons and He ions in a dilute electron gas of a metal   (Site not responding. Last check: 2007-10-17)
Electronic stopping power of protons and He ions in a dilute electron gas of a metal
We compare the electronic energy loss of H- and He-ions in Mg, in order to obtain information about the dynamic screening and the interaction of the screened ion with the electron gas.
A prediction of this theory is that in a dilute electron gas (with v
www.exphys.jku.at /Frames/Public/Abstracts/Abst98/INVESTIG.HTM   (308 words)

  
 TFCBooks -- Tesla Site Glossary
The basic unit of charge, usually denoted by e, is that on the proton or the electron; that on the proton is designated as positive (+e) and that on the electron is designated as negative (-e).
Discharge is sustained by secondary electrons emitted when ions or recombination radiation impact on the cathode; electrons are accelerated away from the cathode and ionize neutral gas in the discharge.
A plasma can be described as a gas to which a specific amount of energy has been added to separate the gas component molecules into a collection of ions, electrons, charge-neutral gas molecules, and other species in varying degrees of excitation.
www.tfcbooks.com /mainpage/glossary.htm   (12768 words)

  
 Two-dimensional electron gas - Wikipedia, the free encyclopedia
Search for Two-dimensional electron gas in other articles.
Look for Two-dimensional electron gas in Wiktionary, our sister dictionary project.
Look for Two-dimensional electron gas in the Commons, our repository for free images, music, sound, and video.
en.wikipedia.org /wiki/Two-dimensional_electron_gas   (121 words)

  
 Publications
G.A. Abrams, S.L. Goodman, P.F. Nealey, M. Franco, and C.J. Murphy, "Nanoscale topography of the basement membrane underlying corneal epithelium of the Rhesus Macaque," Cell and Tissue Research, 299, 39-42, 2000.
G.A. Abrams, S.S. Schaus, S.L. Goodman, P.F. Nealey, and C.J. Murphy, "Nanoscale topography of the corneal epithelial basement membreane and Descemet's membrane of the human," Cornea, 19, 57-64, 2000.
G.A. Abrams, E. Bentley, P.F. Nealey, and C.J. Murphy, "Electron microscopy of the canine corneal basement membranes," Cells Tissues Organs, 170, 251-257, 2002.
www.mrsec.wisc.edu /publications.php   (10619 words)

  
 Vector » Topics in the Theory of Solid Materials (John M Vail) » Paramagnetism and diamagnetism in the ...   (Site not responding. Last check: 2007-10-17)
The electron gas is an oversimplified model of conduction electrons in a metal.
Diamagnetism represents the fact that electrons in such a field have orbits whose perpendicular projections are circular, and the resultant current loops make a different contribution to the magnetic susceptibility.
The treatment of electron paramagnetism is presented here in section 13.2 as a particularly instructive application of quantum statistical thermodynamics.
vector.iop.org /abstract/0750307293/b898c13   (261 words)

  
 Patent 5258631: Semiconductor device having a two-dimensional electron gas as an active layer
The technical concept of using two-dimensional electron gas (hereinafter called "2DEG") formed on a heterojunction interface between n-type AlGaAs (aluminum gallium arsenide) and undoped GaAs (gallium arsenide) for the active layer of a field effect transistor (FET) is disclosed, for example, in Japanese Patent Laid-Open No. 160473/1980.
Speaking semi-macroscopically, the increase of the contact area with the electrode due to the trench means the increase of the electron paths in the contact layer 115 as represented by arrows in FIG.
Though the embodiment described above represents the field effect transistor utilizing the two-dimensional electron gas stored in one set of heterojunction interface, the semiconductor layer structures below the contact layer may have any structure and other compound semiconductors can of course be used as the semiconductor materials for each layer including the contact layer.
www.freepatentsonline.com /5258631.html   (6043 words)

  
 The Tom Bearden Website
The basic idea here -- that electron precession accounts for the Hertzian waves in the electron gas in a transmitting antenna and in a receiving antenna, came from my close colleague and friend, Frank Golden, and I am most happy to give him full credit for this important insight.
An easy way to see that electrons do not interact with that substructured longitudinal zero-vector wave is to visualize both substructure component waves interacting on the electron simultaneously, pushing in opposite directions equally.
Thus the electrons in the nonlinear, phase shift area are hooked and oscillated (precessed) to and fro, producing energy.
www.cheniere.org /books/part4/s28.htm   (635 words)

  
 Friedel Oscillations in 2D Electron Gas Systems at Semiconductor Surfaces   (Site not responding. Last check: 2007-10-17)
The operational principle of the semiconductor electronic devices fabricated so far is based on the control of the number of electrons passing through the active part of devices.
This principle utilizes the feature of electrons as material particles, which had been the excellent description in the classical theory of physics.
Our detailed analysis indicates that the observed oscillations are caused by the scattering of the two-dimensional electron gas accumulated in the near-surface region of the InAs surfaces.
www.brl.ntt.co.jp /J/kouhou/katsudou/report00/E/report13_e.html   (346 words)

  
 IBM Research | Zurich Research Lab | Science & Technology | Atomic/Molecular manipulation
The electrons in the surface state form a two-dimensional electron gas.
Scattering of the electrons in the surface state forms the well-known standing wave patterns.
A small increase of the effective mass of the electrons is observed.
www.zurich.ibm.com /st/atomic_manipulation/refraction.html   (419 words)

  
 Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations
The electrical behavior of a homogeneous electron gas is described by the response function'' K(k omega), defined by a relation that in space-time configuration becomes a nonlocal and acausal relation.
This function is analogous to the inverse of impedance'' in electric circuits and determines how an electrical disturbance propagates in the electron gas and under what circumstances the disturbance becomes oscillatory.
This function is evaluated for an electron gas at absolute zero temperature and at temperatures in the neighborhood of absolute zero, by using the Boltzmann-Vlasov equations and Fermi-Dirac distribution law of electron energies.
www.osti.gov /energycitations/product.biblio.jsp?osti_id=4756172   (285 words)

  
 3. Quantum Mechanics of the Electron Gas
In chapter 2, we showed that the quantum mechanics of the electrons and nuclei which make up real systems can be simplified using the Born-Oppenheimer approximation to separate the motion of the nuclei and electrons.
It is therefore possible to treat the nuclei as stationary and reduce the problem to that of a gas of interacting electrons moving in a static external potential due to the nuclei.
Furthermore, it is possible to make a mapping from the system of interacting electrons to a fictitious system of non-interacting particles which has the same ground-state density.
www.tcm.phy.cam.ac.uk /~pdh1001/thesis/node16.html   (239 words)

  
 Homework--Ch9&11   (Site not responding. Last check: 2007-10-17)
Although we usually apply Fermi-Dirac statistics to free electrons in a conductor, they apply to any system of spin 1/2 particles, including protons and neutrons in a nucleus.
(a) On the basis of the classical free-electron gas model, and assuming that each silver atom contributes one electron to the electron gas, calculate the average time between collisions of the electrons.
Assuming that conduction electrons in silver are described by the Ferm free-electron gas model with E
fluffah.phy.uncwil.edu /phy/moyer/QuantumWeb/homework/hw10.htm   (217 words)

  
 Patent 5272365: Silicon transistor device with silicon-germanium electron gas hetero structure channel
Such type of transistor may be defined as the field effect transistor which is comprised of gallium arsenide and gallium aluminum arsenide, with a Schottky metal contact on the gallium aluminum arsenide layer and two ohmic contacts penetrating into the gallium arsenide layer, serving as the gate, source and drain respectively.
In the HEMT, what is called the "two-dimensional electron gas" spreads inside a non-doped gallium arsenide layer functioning as the channel region, to thereby attain high-speed transistor operations.
The electron mobility of the HEMT can further improved by using the gallium arsenide layer as a channel region, because of its high electron mobility.
www.freepatentsonline.com /5272365.html   (3837 words)

  
 Novel Explanation Offered For Puzzling Electron 'Gas' Experiments
CHAMPAIGN, Ill. -- Recent experiments confirming the existence of a novel conducting phase in a two-dimensional electron "gas" sandwiched between semiconductors have posed a dilemma for scientists seeking to explain their observations.
"In such a device, electrons are confined to move at the interface between the metal oxide and the semiconductor," explained Philip Phillips, a U. of I. professor of physics who led a team that analyzed the experiments, which were carried out elsewhere.
Because the conductivity was independent of temperature at a particular electron density, that density marks the transition between the conducting and insulating phases, Phillips said.
www.eurekalert.org /pub_releases/1998-10/UoIa-NEOF-011098.php   (472 words)

  
 Thermo Electron Gas Detection Equipment - Certified Air Safety
Multi gas monitor is ideal for pre-testing confined spaces in refineries, wastewater treatment plants, fire departments, utilities and many other applications.
The Model 128 is a cost-effective solution for warning of unsafe gas levels in areas such as semiconductor manufacturing, wastewater treatment, garages, warehouses, toll booths, gas bunkers, utilities, and telecommunications industries.
A single gas detector, which allows users to extract a gas sample from deep shafts, tall ceilings, wells, pits and many other locations where it is either difficult or impossible to place a diffusion sensor.
www.certifiedairsafety.com /manuf/thermo.php   (1095 words)

  
 Harnessing Electron Gas Interactions in the Environmental SEM to aid Materials Characterisation (ROPA)   (Site not responding. Last check: 2007-10-17)
The Environmental Scanning Electron Microscope (ESEM) is a rather new form of SEM, which permits observation of wet and insulating samples in their native state, without the need for a conductive coating.
Specifically, if secondary electrons cause ionisation of a gas molecule thereby creating daughter electrons, amplification of the signal by a cascade process occurs.
This has been specifically done with the aim of mixing small amounts of water vapour with a carrier gas, to permit experiments to be done with ice-containing samples at sub-zero temperatures.
www.poco.phy.cam.ac.uk /online/reports/GR-L59849.htm   (529 words)

  
 APS - 2005 APS March Meeting PostDeadline - Event - Optical properties of a spherical 2D electron gas in the presence ...   (Site not responding. Last check: 2007-10-17)
Using the RPA, we calculate the plasmon frequencies of an electron gas on a two-dimensional spherical surface in the presence of a weak magnetic field[1].
We also investigate how the plasmon energies vary as a function of the number of electrons and radius of the sphere.
We discuss how the calculation can be generalized to an electron liquid confined in a spherical shell of finite thickness.
meetings.aps.org /Meeting/MAR05/Event/25801   (167 words)

  
 Rigorous Semiclassical Results for the Magnetic Response of an Electron Gas - Combescure, Robert (ResearchIndex)   (Site not responding. Last check: 2007-10-17)
Abstract: Consider a free electron gas in a confining potential and a magnetic field in arbitrary dimensions.
If this gas is in thermal equilibrium with a reservoir at temperature T > 0, one can study its orbital magnetic response (omitting the spin).
An existence theorem for Vlasov gas dynamics in regions with..
citeseer.lcs.mit.edu /combescure01rigorous.html   (441 words)

  
 Publications of D. M. Ceperley   (Site not responding. Last check: 2007-10-17)
Effects of backflow correlations in the three-dimensional electron gas: quantum Monte Carlo Study, Phys.
Electronic structure of self-assembled quantum dots: comparison between density functional theory and diffusion quantum Monte Carlo, Physica E 8, 260-268 (2000).
Backflow Correlations for the Electron Gas and Metallic Hydrogen, Phys.
www.physics.uiuc.edu /People/Faculty/Ceperley/papers/index.htm   (3516 words)

  
 Session R15 - Semiconductor Heterostructure: Electronic Properties.
The first step consists in evaluating the work done by the polarization field of the sample on the electron (responsible for the polarization) along its classical trajectory in which the electron is regarded as an external time-dependent potential that causes transitions in the target.
Analytical closed-from expressions for the energy-loss spectra for inelastically scattered coherent electron beam are obtained in terms of the exact inverse dielectric function[1].
The width of the quantum point contact may be adjusted, allowing the behavior of the interferometer conductance resonances to be examined in both the multi-mode and the tunneling regimes.
flux.aps.org /meetings/YR97/BAPSMAR97/abs/S5140.html   (2128 words)

Try your search on: Qwika (all wikis)

Factbites
  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.