Ground-state properties of double-wire semiconducting systems

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buir.advisorTanatar, Bilal
dc.contributor.authorMutluay Müstecaplıoğlu, Nihal
dc.date.accessioned2016-01-08T20:15:01Z
dc.date.available2016-01-08T20:15:01Z
dc.date.issued1997
dc.departmentDepartment of Physicsen_US
dc.descriptionAnkara : The Department of Physics and the Institute of Engineering and Science of Bilkent Univ., 1997.en_US
dc.descriptionThesis (Master's) -- Bilkent University, 1997.en_US
dc.descriptionIncludes bibliographical references leaves 50-56.en_US
dc.description.abstractWith the recent advances in nanometer-scale semiconductor device fabrication technology, it became experimentally possible to produce strongly confined electron systems. Quantum wires are among these systems, and are attracting increasing interest due to their potential applications in solid-state device technology such as high-speed transistors, efficient photodetectors and lasers. Quantum wires are quasi-one-dimensional systems where electrons are free to move in one dimension, but their motion is restricted in the remaining two dimensions. Various models for qucisi-one-dimensional structures have been proposed in the literature, such as cylindrical, square-well and parabolic confinements. in this thesis, we examine ground-state correlations in double-quantum-wire systems within the self-consistent scheme of Singwi et ai, namely the STLS approximation. The model we adopt consists of two parallel cylindrically-confined quantum wires. The cases when both wires have electrons as charge carriers and when one wire has electrons while the other has holes are considered. Under the assumption that only one subband is occupied in each quantum wire and there is no tunneling between them, we calculate the local-field factors and static correlation functions. Ground-state energy and collective modes are discussed within the RPA, Hubbard and STLS approximations in order to compare the results. Charge-density-wave instabilities in these structures are examined at small and finite q values. Our numerical results are given for systems where the carrier densities and the radii of both wires are equal. As the charge carrier density is lowered, we observe that the importance of local field corrections increases so that the RPA or Hubbard approximations do not give reliable results in this region. We find that the interwire correlations become quite important for electron-hole systems. Taking into account the exchange-correlation hole around electrons, STLS provides a much better description to this many-body problem compared to the previous models.en_US
dc.description.degreeM.S.en_US
dc.description.statementofresponsibilityMüstecaplıoğlu, Nihal Mutluayen_US
dc.format.extentviii, 56 leavesen_US
dc.identifier.urihttp://hdl.handle.net/11693/17966
dc.language.isoEnglishen_US
dc.publisherBilkent Universityen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectQuasi-one-dimensional electron gasen_US
dc.subjectdouble-quantum-wireen_US
dc.subjectexchange-correlationen_US
dc.subjectlocal-field correctionen_US
dc.subjectstatic structure factoren_US
dc.subjectdensity response functionen_US
dc.subjectdielectric functionen_US
dc.subjectpair correlation functionen_US
dc.subjectground state energyen_US
dc.subjectcollective modesen_US
dc.subjectcharge-density-wave instabilityen_US
dc.subjectrandom phase approximationen_US
dc.subjectHubbard approximationen_US
dc.subjectSTLS approximationen_US
dc.subject.lccQC176.8.E4 M87 1997en_US
dc.subject.lcshQuantum electronics.en_US
dc.subject.lcshSemiconductors.en_US
dc.subject.lcshSolid-state physics.en_US
dc.subject.lcshHubbard model.en_US
dc.titleGround-state properties of double-wire semiconducting systemsen_US
dc.typeThesisen_US

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