<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">JAMP</journal-id><journal-title-group><journal-title>Journal of Applied Mathematics and Physics</journal-title></journal-title-group><issn pub-type="epub">2327-4352</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/jamp.2016.44081</article-id><article-id pub-id-type="publisher-id">JAMP-65880</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Physics&amp;Mathematics</subject></subj-group></article-categories><title-group><article-title>
 
 
  Broadening Thermal Energy Levels and Density States Quasi One-Dimensional Electron Gas
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>.</surname><given-names>J. Baymatov</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>A.</surname><given-names>G. Gulyamov</given-names></name><xref ref-type="aff" rid="aff2"><sup>2</sup></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>A.</surname><given-names>B. Davlatov</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>B.</surname><given-names>B. Uzakov</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib></contrib-group><aff id="aff2"><addr-line>Physico-Technical Institute, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan</addr-line></aff><aff id="aff1"><addr-line>Namangan State University, Namangan, Uzbekistan</addr-line></aff><author-notes><corresp id="cor1">* E-mail:<email>gulyamov1949@mail.ru(AGG)</email>;</corresp></author-notes><pub-date pub-type="epub"><day>13</day><month>04</month><year>2016</year></pub-date><volume>04</volume><issue>04</issue><fpage>706</fpage><lpage>710</lpage><history><date date-type="received"><day>15</day>	<month>February</month>	<year>2016</year></date><date date-type="rev-recd"><day>accepted</day>	<month>23</month>	<year>April</year>	</date><date date-type="accepted"><day>26</day>	<month>April</month>	<year>2016</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p>
 
 
  We have investigated the energy states of a one-dimensional electron gas and analyzed the temperature dependence of the density of states. It is shown that with increasing temperature due to thermal broadening of quantum, levels are blurred.
 
</p></abstract><kwd-group><kwd>Quasi One-Dimensional Electron Gas</kwd><kwd> Density of States</kwd><kwd> Thermal Broadening</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>The current stage of development of solid state physics is characterized by the fact that the main object of study is increasingly not becoming massive semiconductor crystals and thin films, multi-layer thin-film structures, conductive yarns and crystallites. The small size of these structures, in which a direction is comparable to the de Broglie wave, according to the laws of quantum mechanics leads to a change in the energy spectrum of charge carriers [<xref ref-type="bibr" rid="scirp.65880-ref1">1</xref>] . The spectrum becomes discrete for movement along a movement axis koto&#172;roy limited.</p><p>The main dimensional quantum structures are structures with two-dimensional electron gas-epitaxial film MIS structure, heterostructure, etc.; dimensional structure with gas-kvanto&#172;vye yarn or wire; structure with zero-dimensional gas-quantum dots, boxes, crystallites.</p><p>Structures in which the movement of charge carriers is free only along one axis, and along the other two limited two-dimensional quantum well, are known as quantum wires or wires. The energy spectrum associated with the movement of charge carriers across the quantum wire is discrete due to the size quantization; and associated with the movement along the filament is continuous. The charge carriers are in such a one-dimensional electron gas [<xref ref-type="bibr" rid="scirp.65880-ref1">1</xref>] .</p><p>Quantum yarn is one-dimensional electronic system where the electron motion is severely restricted in both directions of the three axes and along the thread remains free [<xref ref-type="bibr" rid="scirp.65880-ref1">1</xref>] [<xref ref-type="bibr" rid="scirp.65880-ref2">2</xref>] . All the basic properties of quantum electronic yarn defined dispersion and the dependence of energy on momentum. The range of knowledge allows us to calculate all the equilibrium properties of the system. The most important characteristic of the electronic system is the density of states. We consider the expression density of states of a quantum wire in view of its temperature dependence. The temperature dependence of the density of surface states at the interface between the semiconductor and dielectric is considered in [<xref ref-type="bibr" rid="scirp.65880-ref3">3</xref>] . It has been shown that due to the thermal broadening of the discrete, spectrum is converted into a continuous spectrum of surface states. The effect of temperature on the thermodynamic density of states of a quantum wire has not been studied.</p><p>The aim of this work is to study the effect of temperature on the thermodynamic density of states of a quantum wire.</p></sec><sec id="s2"><title>2. Energy Spectrum and Density of States</title><p>This work is devoted to studying the effect of temperature on the density of states of the one-dimensional electron gas (OEG). Thermal broadening of the levels described using statistics Shockley-Read-Hall [<xref ref-type="bibr" rid="scirp.65880-ref3">3</xref>] . It is shown that with increasing temperature due to thermal broadening of the discrete levels of density of states become smooth.</p><p>The range of media in a one-dimensional pit is [<xref ref-type="bibr" rid="scirp.65880-ref1">1</xref>] [<xref ref-type="bibr" rid="scirp.65880-ref2">2</xref>]</p><disp-formula id="scirp.65880-formula2289"><label>(1)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x6.png"  xlink:type="simple"/></disp-formula><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x7.png" xlink:type="simple"/></inline-formula>.</p><p>Here, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x8.png" xlink:type="simple"/></inline-formula>is the effective mass of the carrier at the bottom of the zone; <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x9.png" xlink:type="simple"/></inline-formula>is pit width. To find the density of states, we use the equation of the total number of particles. After summation over the back it has the form</p><disp-formula id="scirp.65880-formula2290"><label>(2)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x10.png"  xlink:type="simple"/></disp-formula><p>Here,<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x11.png" xlink:type="simple"/></inline-formula>: Sample dimensions along the axes x,<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x12.png" xlink:type="simple"/></inline-formula>: Heaviside unit function</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x13.png" xlink:type="simple"/></inline-formula>.</p><p>From (2) we have</p><disp-formula id="scirp.65880-formula2291"><label>(3)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x14.png"  xlink:type="simple"/></disp-formula><p>Hence, we obtain expressions for the 1D density of states [<xref ref-type="bibr" rid="scirp.65880-ref4">4</xref>]</p><disp-formula id="scirp.65880-formula2292"><label>. (4)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x15.png"  xlink:type="simple"/></disp-formula><p>Here,</p><disp-formula id="scirp.65880-formula2293"><label>. (4a)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x16.png"  xlink:type="simple"/></disp-formula><p>Plot the functions <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x17.png" xlink:type="simple"/></inline-formula> at L<sub>1</sub> = 10<sup>−8</sup> m and L<sub>2</sub> = 1.5 &#180; 10<sup>−8</sup> m.</p></sec><sec id="s3"><title>3. Temperature Dependence of the Density of States</title><p>Let us now consider how we can describe the effect of heat on the broadening of the thermodynamic density of states. Its accounting functions via GN (i.e. the derivative of the probability by thermal energy generation energy states E) is given in [<xref ref-type="bibr" rid="scirp.65880-ref3">3</xref>] . It was shown that the temperature dependence of the density of states can be described by the decomposition of the density of states in a series of GN-functions</p><disp-formula id="scirp.65880-formula2294"><label>(5)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x18.png"  xlink:type="simple"/></disp-formula><p>Here,<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x19.png" xlink:type="simple"/></inline-formula>: the density of states at zero temperature (4), and GN-function has the form</p><disp-formula id="scirp.65880-formula2295"><label>(6)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x20.png"  xlink:type="simple"/></disp-formula><p>The considered energy interval<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x21.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x22.png" xlink:type="simple"/></inline-formula>divided into equal small pieces value energy <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x22.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x23.png" xlink:type="simple"/></inline-formula>, then<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x22.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x23.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x24.png" xlink:type="simple"/></inline-formula>. Function (6) with <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x22.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x23.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x24.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x25.png" xlink:type="simple"/></inline-formula> converted into the Dirac delta function<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x22.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x23.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x24.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x25.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x26.png" xlink:type="simple"/></inline-formula>. In the limit, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x22.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x23.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x24.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x25.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x26.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/4-1720527x27.png" xlink:type="simple"/></inline-formula>sum (5) can be replaced by an integral. Then</p><disp-formula id="scirp.65880-formula2296"><label>(7)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x28.png"  xlink:type="simple"/></disp-formula><p>Supplying (4) to (7), we obtain</p><disp-formula id="scirp.65880-formula2297"><label>(8)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/4-1720527x29.png"  xlink:type="simple"/></disp-formula><p>Plot the temperature dependence of the density of states by Formula (8) at different temperatures believing.</p><p>The density of states of the two-dimensional electron gas, quantum wire is similar to the density of states of a three-dimensional electron gas in a quantizing magnetic field. The difference between the density of states of these systems due to the fact that the distance between the discrete states in a bulk semiconductor is determined by the magnitude of the magnetic field, and in the quantum filament transverse dimensions of two-dimensional quantum well. Due to the interaction of the electrons with the lattice vibrations peak heights density of states decreases and the width increases.</p><p><xref ref-type="fig" rid="fig2">Figure 2</xref> shows plots of the density of states of one-dimensional electron gas. We analyze the results of numerical calculations. The figure shows with solid lines the density of states graphics calculated at T = 10 K. This schedule is almost the same as in <xref ref-type="fig" rid="fig1">Figure 1</xref>, which does not take into account the temperature dependence of the density of states. However, the temperature difference between the zero lead to the fact that the height of the peaks in <xref ref-type="fig" rid="fig2">Figure 2</xref> are reduced about 1.5 times. An increase in temperature greatly reduces the height of the peaks, the discrete quantization levels cross a two-dimensional quantum well. A further increase in temperature to T = 90 K, more blurs the peaks turning them into low humps of the density of states. At a temperature T = 300 K, the density of states in one-dimensional gas becomes a monotonically increasing function of energy where the discrete levels are almost invisible.</p><p><xref ref-type="fig" rid="fig3">Figure 3</xref> shows the dependence of the density on the temperature in the three-dimensional image. From <xref ref-type="fig" rid="fig3">Figure 3</xref> clearly shows that the temperature strongly affects the thermodynamic density of states. At low temperatures,</p><fig id="fig1"  position="float"><label><xref ref-type="fig" rid="fig1">Figure 1</xref></label><caption><title> Dependence of density of states of 1D electron gas of energy L<sub>1</sub> = 10<sup>−8</sup> and L<sub>2</sub> = 1.5 &#180; 10<sup>−8</sup></title></caption><graphic mimetype="image"   position="float"  xlink:type="simple"  xlink:href="http://html.scirp.org/file/4-1720527x30.png"/></fig><fig id="fig2"  position="float"><label><xref ref-type="fig" rid="fig2">Figure 2</xref></label><caption><title> Dependence of density of states of 1D electron gas on the energy for different temperatures: L<sub>1</sub> = 10<sup>−8</sup> m and L<sub>2</sub> = 1.5・10<sup>−8</sup> m</title></caption><graphic mimetype="image"   position="float"  xlink:type="simple"  xlink:href="http://html.scirp.org/file/4-1720527x31.png"/></fig><fig id="fig3"  position="float"><label><xref ref-type="fig" rid="fig3">Figure 3</xref></label><caption><title> Dependence of density of states of 1D electron gas on the energy and temperature in three- dimensional space: L<sub>1</sub> = 10<sup>−8</sup> m and L<sub>2</sub> = 1.5・10<sup>−8</sup> m</title></caption><graphic mimetype="image"   position="float"  xlink:type="simple"  xlink:href="http://html.scirp.org/file/4-1720527x32.png"/></fig><p>the density of states of the one-dimensional electron gas is strongly oscillating electron energy functions. With increasing temperature, the density oscillations subside, and at high temperatures turn into monotonically increasing function of energy</p></sec><sec id="s4"><title>4. Conclusion</title><p>On the basis of this work, we can conclude that the temperature dependence of the density of the Kantian threads due to thermal broadening of discrete energy states. Thermal broadening of states can be described by the temperature dependence of the probability of filling the energy levels. At temperatures where the thermal kT energy of the electrons is much smaller than the distance between adjacent discrete levels ΔE<sub>nl</sub><sub>,</sub>, thermal broadening is not significantly altered the density of states and the peaks in the density of states plots will stand out sharply. The increase in temperature due to the thermal broadening of the peaks of the density gradually eroded discrete levels. At temperatures of the order of kT distances between leveled kT ≤ ΔE<sub>nl</sub>, density thermodynamic states are smoothed. Thus, the thermodynamic state density of electrons in the quantum wire is temperatures low power oscillating function at high temperatures, and it is converted into a monotonically increasing function of energy.</p></sec><sec id="s5"><title>Cite this paper</title><p>P. J. Baymatov,A. G. Gulyamov,1 1,A. B. Davlatov,B. B. Uzakov, (2016) Broadening Thermal Energy Levels and Density States Quasi One-Dimensional Electron Gas. Journal of Applied Mathematics and Physics,04,706-710. doi: 10.4236/jamp.2016.44081</p></sec></body><back><ref-list><title>References</title><ref id="scirp.65880-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Shik, A.Y., Bakueva, L.G., Musikhin, S.F. and Rykov, S.A. (2001) Physics of Low-Dimensional Systems. -SPb.: Science.</mixed-citation></ref><ref id="scirp.65880-ref2"><label>2</label><mixed-citation publication-type="other" xlink:type="simple">Dragunov, V.P., Unknown, I.G. and Gridchin, V.A. (2006) Fundamentals of Nanoelectronics. Fizmatkniga, Moskva.</mixed-citation></ref><ref id="scirp.65880-ref3"><label>3</label><mixed-citation publication-type="other" xlink:type="simple">Gulyamov, G. and Sharibaev, N.Y. (2011) FTP (Fizika Technika Poluprovodnikov), 45, 178-182.</mixed-citation></ref><ref id="scirp.65880-ref4"><label>4</label><mixed-citation publication-type="other" xlink:type="simple">Shik, A.Y. (1997) Quantum Yarn. Soros Educational Journal, No. 5.</mixed-citation></ref></ref-list></back></article>