Now showing items 115-134 of 225

    • Low-temperature thermodynamics of finite and discrete quartic quantum oscillator in one dimension 

      Sıddıki, Afif (Bilkent University, 1999)
      I.' this work we examined a quartic Hamiltonian using two different approaches. We first introduced a mean-field Gaussian approximation in order to handle this Hamiltonian analytically and observed that this approximation is ...
    • Magnetism of transition metal nanowires 

      Ataca, Can (Bilkent University, 2008)
      In this thesis we investigated structural, electronic and magnetic properties of 3d (light) transition metal (TM) atomic chains and Cr nanowires using firstprinciples pseudopotential plane wave calculations. Infinite ...
    • Manipulation and control of collective behavior in active matter systems 

      Pinçe, Erçağ (Bilkent University, 2016-11)
      Active matter systems consist of active constituents that transform energy into directed motion in a non-equilibrium setting. The interaction of active agents with each other and with their environment results in collective ...
    • Many-body effects in selected two-dimensional systems 

      Subaşı, A Levent (Bilkent University, 2009)
      In this thesis we study many-body effects in three distinct two-dimensional systems. The two dimensional electron gas is a model system yielding to basic analytical and computational theoretical ideas of many-body physics ...
    • Many-body interaction effects in quasi-one-dimensional photo-excited electron-hole systems 

      Güven, Kaan (Bilkent University, 1999)
      The work in this thesis concerns rnany-body interaction effects in a quasi-onedimensional electron-hole plasma, which may be generated under intense photoexcitation in a semiconductor quantum-well wire. In particular, ...
    • Many-body properties of one-dimensional systems with contact interaction 

      Demirel, Ekrem (Bilkent University, 1999)
      The one-dimensional electron systems are attracting a lot of interest because of theoretical and technological implications. These systems are usually fabricated on two-dimensional electron systems by confining the ...
    • Mean-field renormalization group theory of the t-J model 

      Şen, Cengiz (Bilkent University, 2002)
      The quantum nature of the high temperature superconductivity models makes analytical approaches to these systems almost impossible to implement. In this thesis, a computational study of the one and two dimensional t − J ...
    • Mechanical and electronic properties of metal chain nanowires 

      Çakır, Deniz (Bilkent University, 2003)
      The fabrication of stable gold monoatomic chains suspended between two gold electrodes is one of the milestones in nanoscience and technology, since miniaturization of the electronic components is one of the great ...
    • Metal coverage on single-wall carbon nanotubes : metal nanoring and nanotube formation 

      Bağcı, V M Kemal (Bilkent University, 2002)
      The carbon nanotubes are welcomed as the basis element for electronic and opto-electronic devices of nanometers size, the size of a few atoms. The question of crucial importance in the physics of utilization of nanotubes ...
    • Microfabrication of micro Hall sensors on GaAs and INSB for scanning hall probe microscopy 

      Kaval, Mehmet Murat (Bilkent University, 2001)
      Different techniques have been developed to investigate the surface magnetic structure of materials, including Hall probe, scanning superconductivity quantum interference device (SQUID) and magnetic force microscopies ...
    • Microfluidic based differential electrochemical sensors 

      Akay, Özge (Bilkent University, 2013)
      Lab-on-a-chip systems aim to integrate analytical techniques on a single chip to achieve high-throughput measurements with little reagent. Microfluidic devices use the advantage of fluid dynamics in microscale to generate ...
    • A microscopic approach to phononic energy transfer in nano structures 

      Özpineci, Altuğ (Bilkent University, 1999)
      Understanding of mechanisms for the energy transfer from and/or through nano particles in contact with the large samples have become important in various biological processes, molecular electronics and friction. In this ...
    • Mixtures of charged-neutral superfluids 

      Ünal, Fatmanur (Bilkent University, 2016-12)
      Motivated by the developments of artificial magnetic fields (AMFs) enabling cou- pling to the neutral particles of ultracold quantum gases, we have theoretically studied charged-neutral mixtures in various settings. The ...
    • Model description of friction on planar and buckled two dimensional materials 

      Uzlu, Hasan Burkay (Bilkent University, 2018-01)
      The law of friction has been known since the 18th century but yet, the development on the tribology field was established in the last decades mainly by the invention of frictional force microscope (FFM), which enabled ...
    • Modeling of semiconductor devices based on quantum wells: quantum cascade laser as an example 

      Abbasian, Hamed (Bilkent University, 2018-02)
      It has been two decades since the quantum-cascade lasers (QCLs) have emerged in 1994 for the first time. As time goes on, QCLs reach to higher points scientifically and economically and the usage of QCLs devices continually ...
    • Monolithic and hybrid silicon-on-insulator integrated optical devices 

      Kiyat, İsa (Bilkent University, 2005)
      Silicon, the basic material of electronics industry is rediscovered nowadays for its potential use in photonics and integrated optics. The research activity in silicon integrated optics have been speeding up during the ...
    • Multi-exciton states in flexible Rydberg aggregates 

      Abumwis, Ghassan F.M. (Bilkent University, 2017-07)
      Flexible Rydberg aggregates, assemblies of highly excited atoms, provide a platform to investigate quantum phenomena like energy transport and conical intersections. This can be achieved by doping the aggregate with an ...
    • Multi-frequency fluxgate magnetic force microscopy 

      Aktaş, Ozan (Bilkent University, 2008)
      In the recent years, progress in atomic force microscopy (AFM) led to the multifrequency imaging paradigm in which the cantilever-tip ensemble is simultaneously excited by several driving forces of different frequencies. ...
    • Nanoscience for sustainable energy production 

      Ataca, Can (Bilkent University, 2011)
      Hydrogen economy towards the utilization of hydrogen as a clean and sustainable energy source has three ingredients. These are (i) hydrogen production; (ii) hydrogen storage; and (iii) fuel cells. Optimization of fuel ...
    • Negative refraction using true left-handed metamaterials 

      Aydın, Koray (Bilkent University, 2004)
      Left-handed materials and negative refraction attracted a great amount of attention in recent years due to their unique physical properties. It is possible to obtain a left-handed material by combining a novel artificial ...