Browsing Theses - Department of Physics by Title
Now showing items 116-135 of 233
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Long wavelength GaAs based hot electron photoemission detectors
(Bilkent University, 1999)The increasing rate of telecommunication alters both science and technology, and demands high performance components. Photo detectors are essential components of optoelectronic integrated circuits and fiber optic ... -
Low dimensional structures for optical and electrical applications
(Bilkent University, 2008)Low dimensional structures such as quantum dots have been particularly attractive because of their fundamental physical properties and their potential applications in various devices in integrated optics and microelectronics. ... -
Low loss optical waveguides and polarization splitters with oxidized AlxGa1-xAs layers
(Bilkent University, 1998)Low propagation loss waveguides, operating at 1.55 fim optical wavelength, are fabricated utilizing oxidized AhGai_a;As layers. MBE grown multilayer semiconductor heterostructures are characterized before and after ... -
Low-temperature thermodynamics of finite and discrete quartic quantum oscillator in one dimension
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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
(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 ... -
A Monte Carlo study of Maxwell’s demon coupled to finite quantum heat baths
(Bilkent University, 2020-09)When Maxwell’s demon was introduced, it raised the question: Is there a way to decrease an isolated system’s entropy, even though it was forbidden by the second law of thermodynamics. Then, a new idea which considered ...
