Now showing items 1-20 of 218

    • Electronic structure of Si/Ge semiconductor superlattices 

      Gülseren, Oğuz (Bilkent University, 1988)
      A brief review about the two dimensional electron systems and especially band offsets is given. The electronic properties of the Si„/Ge„(001) strained superlattices as a function of the superlattice periodicity and the ...
    • Atomic theory of the scanning tunneling microscope 

      Tekman, Ahmet Erkan (Bilkent University, 1988)
      The Scanning Tunneling Microscope is proven to be one of the most powerful tools for surface structure determination. Present theories are able to explain the operation of the microscope when the tip is far from the ...
    • High Tc superconductivity 

      Gedik, M. Zafer (Bilkent University, 1989)
      critical summary of the recent developments in high temperature superconductivity is given. Physical properties of the new materials are summarized. The new theories proposed to explain high Tc are reviewed. In the case ...
    • Construction of a scanning tunneling microscope and first results 

      Oral, Ahmet (Bilkent University, 1990)
      In this thesis, construction of a Scanning Tunneling Microscope in air is explained. A step motor sample approach mechanism and a tripod scanner are used in the construction. Atomic resolution images of graphite samples ...
    • Ballistic transport and tunneling in small systems 

      Tekman, A Erkan (Bilkent University, 1990)
      Ballistic transport and tunneling of electrons in mesoscopic systems have become one of the most important subjects of condensed matter physics. The quantum point contacts and scanning tunneling microscope form the basic ...
    • Electronic structure of low dimensional semiconductor systems 

      Gulseren, Oguz (Bilkent University, 1992)
      Recent progress made in the growth techniques has led to the fabrication of the artificial semiconductor systems of lower dimension. Electrons and holes in these materials have quantization different from those of the ...
    • Superconducting systems of low dimensionality 

      Gedik, M. Zafer (Bilkent University, 1992)
      It is possible to call the last five years as the golden age of superconductivity. The two most important developments in the field are the discovery of copper oxide and fullerene superconductors. In this work, some ...
    • Phase transitions in tetrahedral Ising lattices 

      Kabakçıoğlu, Alkan (Bilkent University, 1993)
      After a review of the Renormalization CJroup theory, the phase diagram of unisotro])ic tetrahedral Ising lattice is explored l)y the motivation gained through the recent experimental findings about SiGe alloys. ...
    • Al(x)Ga(1-x)As/GaAs graded index separate confinement heterostructure single quantum well lasers 

      Bozkurt, Mümtaz Koray (Bilkent University, 1994)
      "Stimulated emission of photons could be produced in semiconductors by recombination of carriers injected across a p-n junction This idea was first suggested by Basov et al} in 1961. Soon afterwards diode lasers were ...
    • Fabrication, characterization, and extraction of GaAs mesfets 

      Ata, Erhan Polatkan (Bilkent University, 1994)
      Metal Semiconductor Field Effect Transistor (MESFET) is the most widely used active element of today’s microwave industry. After development of the MESFET technology, the microwave industry gained a high acceleration, ...
    • Hard spin mean field theory of 3D stacked-triangular-lattice system 

      Akgüç, Gürsoy Bozkurt (Bilkent University, 1994)
      Closed form solution of ‘Hard spin mean field theory’ is constructed and applied to ‘Three dimensional stacked-triangular-system’. The phase diagram of this system is examined. ‘Free energy’ is calculated to reveal ...
    • Ridge waveguide GaAS 

      Türkoğlu, Abdullah Kamuran (Bilkent University, 1994)
      The study of solid-state laser structures in low dimensions has gained great deal of attention in recent years. The theory originated in early 1960s developed really fast along with new fabrication methods bringing ...
    • Controlled lateral and perpendicular motion of atoms on metal surfaces 

      Buldum, Alper (Bilkent University, 1994)
      Nanoscale modification of matter has been the subject of interest. Recently, several experimental studies have demonstrated that by using a scanning tunneling microscope one can translate atoms on metal surfaces to a ...
    • Investigation of Si1-xGex alloy formation by using STM 

      Oral, Ahmet (Bilkent University, 1994)
    • Time dependent study of quantum bistabiliity 

      Ecemiş, Mustafa Ihsan (Bilkent University, 1995)
      The analysis of quantum transport phenomena in small systems is a prominent topic of condensed matter physics due to its numerous technological applications. The current analytical theories are not adequate for ...
    • Rabi oscillations in an exciton-polariton system 

      Müstecaplıoğlu, Özgür Esat (Bilkent University, 1995)
      The pure qiiaiitum model d(\scril)ing lîahi oscillations of exciton-polaritons in a ınicro-cavity is consid(‘r(‘(l. IMiolon-c'Xcilon intiT’action Hamiltonian is diagonalized with the aid of Bogoliihov canonical transformations ...
    • Phonon renormalization effects in low dimensional electron-hole systems 

      Güven, Kaan (Bilkent University, 1995)
      Ia)vv (linuMisioiial sciniromluclor st i iid iii4's lia\4‘ 1и‘(М1 an (‘Xt(Misiv(‘ i4\soa,rrh iwcix ill (4)iul(4iscd iiiatlcr physics. In j^aii iculai', iiindi (‘llorl has 1)(Ч'п dcvolnd to lhc‘ study ol ciuasi-one-diiiK'iisional ...
    • Supercurrents and persistent currents in strongly correlated electron systems 

      Boyacı, Hüseyin (Bilkent University, 1995)
      The lull understanding· ol’the solution Гог the 1-tl Hubbard model is of interest in its own right, and may provide clues to the understanding of higher dimensioned systiMiis. We have found tin? exact solution of tlie ...
    • Approximation methods in the polaron theory: applications to low dimensionally confined polarons 

      Senger, R Tuğrul (Bilkent University, 1996)
      The pelaron problem has been of interest in condensed matter physics cind held theory tor cibout half a century. Within the framework of Vcist variety of theoreticcil approximations, the bulk polaron properties have been ...
    • Fabrication and characterization of high speed resonant cavity enhanced Schottky photodiodes 

      Islam, M Saiful (Bilkent University, 1996)
      High speed, high external quantum efficiency and narrow spectral linewidth make resonant cavity enhanced (RC E) Schottky photodetector a good candidate for telecommunication applications. In this thesis, we present our ...