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Topic: Density of states


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  Density of states - Wikipedia, the free encyclopedia
Density of states (DOS) is a property in statistical and condensed matter physics that quantifies how closely packed energy levels are in some physical system.
To calculate the density of energy states of a particle we first calculate the density of states in reciprocal space (momentum- or k-space).
To find the density of energy states, the relation between energy and momentum for a particular particle is used, to express k and dk in g(k)dk in terms of E and dE.
en.wikipedia.org /wiki/Density_of_states   (453 words)

  
 Britney Spears' Guide to Semiconductor Physics: Density of States
As we consider the density of states, the situation is complicated by energy degeneracy.
The density of states at an energy E is the number of k-states per unit volume contained with the annulus of radius k and thickness dk.
It is significant that the 2-d density of states does not depend on energy.
britneyspears.ac /physics/dos/dos.htm   (1437 words)

  
 Stefan Birner: Density of states (Essay)
/L. To calculate the density of states the number of wavevectors in the shaded circular ring between k and k+dk must be determined.
The density of states is, for instance, used to obtain the heat capacity
Einstein model of the density of states to derive the heat capacity (used to approximate the optical phonon part of the phonon spectrum)
www.asamnet.de /~birners/public_html/density.html   (953 words)

  
 Photon Energy Density   (Site not responding. Last check: 2007-10-08)
This distribution determines the probability that a given energy state will be occupied, but must be multiplied by the density of states function to weight the probabability by the number of states available at a given energy.
The final density of states as a function of energy is then the deriviative of this population with respect to energy
The density of states in terms of frequency or wavelength can be obtained by expressing the number of states per unit volume in terms of frequency or wavelength.
hyperphysics.phy-astr.gsu.edu /hbase/quantum/phodens.html   (330 words)

  
 Global density of states method
In the global density of states method, the global moments are used to construct recursion coefficients from which the density of states, band energy and atomic forces are evaluated.
In summary, the use of the global density of states leads to a reduced rate of convergence of the energy with number of moments as compared with the local densities of states for inhomogeneous systems.
This has to be weighed against the chief benefit of using the global density of states, namely that the analytical forces are exact derivatives of the energy.
www.cmmp.ucl.ac.uk /~drb/Comparison/node7.html   (467 words)

  
 Density of states
The density of states in a semiconductor equals the density per unit volume and energy of the number of solutions to Schrödinger's equation.
This assumption does not affect the result since the density of states per unit volume should not depend on the actual size or shape of the semiconductor.
The density of states is zero at the bottom of the well as well as for negative energies.
ece-www.colorado.edu /~bart/ecen3320/newbook/chapter2/ch2_4.htm   (498 words)

  
 2.3 Density of states calculation
Calculation of the density of states in 1, 2, and 3 dimensions
The result is a density per unit volume and energy in the case of a three-dimensional semiconductor.
The case for the quantum wire is further complicated by the degeneracy of the energy levels: for instance a two-fold degeneracy increases the density of states associated with that energy level by a factor of two.
ece-www.colorado.edu /~bart/book/dos.htm   (552 words)

  
 Encyclopedia: Density of states   (Site not responding. Last check: 2007-10-08)
Density of states (DOS) is a property in condensed matter physics that quantifies how closely packed energy levels are in some physical system.
A solid is a state of matter, characterized by a definite volume and a definite shape (i.
Dimension (from Latin measured out) is, in essence, the number of degrees of freedom available for movement in a space.
www.nationmaster.com /encyclopedia/Density-of-states   (555 words)

  
 Existence And Uniqueness Of The Integrated Density Of States For Schrödinger Operators With Magnetic Fields And ...   (Site not responding. Last check: 2007-10-08)
10 The density of states and the spectral shift density of rand..
2 the density of states of Schrdinger operators with a random..
1 Asymptotic expansion for the density of states of the magnet..
citeseer.ist.psu.edu /hupfer00existence.html   (989 words)

  
 Density of states -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-08)
Density of states (DOS) is a property in (Click link for more info and facts about condensed matter physics) condensed matter physics that quantifies how closely packed (A definite stable energy that a physical system can have; used especially of the state of electrons in atoms or molecules) energy levels are in some material.
It is often expressed as a function N(E) of the (Click link for more info and facts about internal energy) internal energy E.
A more precise definition is as follows: N(E) dE is the number of allowed energy levels per unit volume of the material, within the energy range E to E + dE.
www.absoluteastronomy.com /encyclopedia/d/de/density_of_states.htm   (137 words)

  
 Density of States dsn   (Site not responding. Last check: 2007-10-08)
The description of electronic states in solids is similar in many respects to the description of normal modes for mass points on a string.
In the free-electron approximation, the energy of a state is proportional to the square of k, the vector from the origin to the state's location in k-space.
Brillouin zones containing one million cubes are defined for the sc, fcc, and bcc structures, and are scanned to generate a histogram with one hundred energy divisions.
www.kw.igs.net /~jackord/bp/ds.html   (370 words)

  
 Integrated Density of States for Ergodic Random (ResearchIndex)   (Site not responding. Last check: 2007-10-08)
16 the density of states of Schrodinger operators with a rando..
7 Density of states in spectral geometry (context) - Adachi, Sunada - 1993
1 Density of states of self adjoint operators with almost peri..
citeseer.ist.psu.edu /664141.html   (678 words)

  
 Edinburgh Research Archive : Item 1842/233   (Site not responding. Last check: 2007-10-08)
Density of states calculations for the tight-binding model with diagonal disorder are presented.
An instanton approach is used to calculate the tails of the spectrum, including all prefactors.
Furthermore, an effective-medium approximation is used to calculate the density of states in the band.
hdl.handle.net /1842/233   (133 words)

  
 Density of States   (Site not responding. Last check: 2007-10-08)
Self-consistent density of states for a single- and double-quantum-well structure in a parallel magnetic field
Density of states for double-barrier quantum-well structures under the influence of external fields and phase-breaking scattering
Density of states and optical-absorption spectra of shallow impurities in quantum wells under the influence of a longitudinal electric field
www.edu.ioffe.ru /links/pub/?ref=6107   (1858 words)

  
 Density of States
We start from the number of states inside a sphere with radius k in phase space.
The density of states D is primarily a density on the energy scale, and only secondarily a density in space.
Inserting the density of states from above with the abbreviation
www.tf.uni-kiel.de /matwis/amat/semi_en/kap_2/basics/b2_1_8.html   (459 words)

  
 Behaviour of the density of states
be the total number of microscopic states which satisfy these constraints.
In other words, the density of states varies like the extensive macroscopic parameters of the system raised to the power of the number of degrees of freedom.
Since thermodynamic systems generally possess a very large number of degrees of freedom, this result implies that the density of states is an exceptionally rapidly increasing function of the energy and volume.
farside.ph.utexas.edu /teaching/sm1/lectures/node30.html   (470 words)

  
 Density of states (DOS)   (Site not responding. Last check: 2007-10-08)
To compute the density of states, a self-consistent calculation has to be done first to get the wave functions.
This will produce a file ``DOS'' in a suitable format for xmgr (it is an ascii text file, and has comments in there).
The density of states is output in units of states/eV/unit cell.
www.tcm.phy.cam.ac.uk /~jry20/paratec/doc/node61.html   (91 words)

  
 Density of states plot
If `all' is entered, then the total density of states is plotted.
Entering the name of one or several atoms yields a plot of the partial density of states associated with these atoms.
If the name of a class of atoms augmented by `-' and an orbital character symbol is entered, only the partial density of states associated with these atoms and this specific
www.fkf.mpg.de /andersen/LMTODOC/node177.html   (444 words)

  
 The Density of States
If there is more than one energy level with the same energy, and we replace the sum over individual states with a sum over allowed energies, we need to include a factor in front of the Boltzmann factor for degenerate levels so that they are counted often enough.
The picture above shows a graphical representation of the allowed states in
The density of states is the number of states within an infinitesimal range of
theory.ph.man.ac.uk /~judith/stat_therm/node80.html   (172 words)

  
 List Of U.S. States By P... Encyclopedia Article, Definition, History, Biography   (Site not responding. Last check: 2007-10-08)
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 List Of U.S. States By Population ... Encyclopedia Article, Definition, History, Biography   (Site not responding. Last check: 2007-10-08)
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 List Of U.S. States By Po... Encyclopedia Article, Definition, History, Biography   (Site not responding. Last check: 2007-10-08)
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encyclopedia.localcolorart.com /encyclopedia/List_of_U.S._states_by_po...   (177 words)

  
 Density of States of a Hamiltonian system   (Site not responding. Last check: 2007-10-08)
Subject: Density of States of a Hamiltonian system
I have a small question for people who have experience in calculating the eigenvalues of extremely large matrices viz.
I am interested in evaluating the Density of States (DOS) of this matrix (real and symmetric).
www.csc.fi /math_topics/Mail/NANET96/msg00093.html   (108 words)

  
 Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations
Energy Citations Database (ECD) Document #7215814 - Electronic density of states.
Availability information may be found in the Availability, Publisher, Research Organization, Resource Relation and/or Author (affiliation information) fields and/or via the "Full-text Availability" link.
For a journal article, please see the Resource Relation field.
www.osti.gov /energycitations/product.biblio.jsp?osti_id=7215814   (78 words)

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