Theses - Department of Physics
Faculty of Science
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Investigation of optical residual absorption in graphene
(Bilkent University, 2018-03)Graphene, a 2-dimensional crystal of carbon, can absorb 2.3% of light over a very broad spectrum. Doped graphene, however has a gap in optical absorption due to the Pauli blocking principle. For doped graphene, the interband ... -
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 ... -
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 ... -
Deformation and finite size effects in cooperative molecular motors
(Bilkent University, 2002-07)Motor protein systems have been of considerable interest lately. In these studies muscle contraction is modeled as the sliding of two filaments made of protein particles over one another, that is the sliding of the ... -
Tight binding modeling of two dimensional and quasi-two dimensional materials
(Bilkent University, 2017-10)Since the advent of graphene, two-dimensional (2D) materials have consistently been studied owing to their exceptional electronic and optical properties. While graphene is completely two-dimensional in nature, its other ... -
Unconventional superconductivity in two dimensional time reversal symmetric noncentrosymmetric superconductors
(Bilkent University, 2017-09)In this thesis we study unconventional pairing observed in noncentrosymmetric superconductors by using spin dependent pairing potentials under the maximal C∞v and the time reversal symmetries (Θ-phase). The lack of ... -
Size controlled germanium nanocrystals in dielectrics : structural and optical analysis and stress evolution
(Bilkent University, 2017-09)Group IV semiconductor nanocrystals, namely silicon and germanium have attracted much interest in the past two decades due to their broad applications in photovoltaic, memory, optoelectronic, medical imaging and ... -
Energy and angular momentum transfer with circular Rydberg states
(Bilkent University, 2017-08)Circular states belong to a class of Rydberg states having maximum angular momentum. These states, compared to other Rydberg states, have longer lifetimes, and in the classical limit resemble circular Bohr-like orbits. ... -
Analysis of the magnetic translation group and investigation of a one-dimensional topological model
(Bilkent University, 2017-08)The periodicity of a space lattice in presence of a uniform magnetic eld is preserved. During this thesis, we will study a set of modi ed translation operators which commute with the e ective Hamiltonian of an electron ... -
Nonlinear and far-from-equilibrium dynamics of optical pulses in fiber oscillators
(Bilkent University, 2017-08)Fundamentals of mode locking of lasers have been extensively studied and well established for the last three decades. However, it continues to be an intensely studied field. The continued interest is, in part, due to the ... -
First principles study of 2D gallium nitride and aluminium nitride in square-octagon structure
(Bilkent University, 2017-08)This thesis, deals with the planar free-standing, single-layer, square-octagon (SO) structures of GaN and AlN. We investigated single-layer and multilayer so-GaN and so-AlN structures, their stability, electronic properties ... -
Multi-exciton states in flexible Rydberg aggregates
(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 ... -
Braph : a toolbox developed for brain graph analysis of various imaging modalities
(Bilkent University, 2017-03)Complex systems, like the human brain, are composed of a huge number of interacting elements showing complex patterns. Graph theory provides a mathematical toolbox for investigating the role of each element in these systems. ... -
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 ... -
Analysis of nonequilibrium steady-states
(Bilkent University, 2016-12)Non-equilibrium is the state of the almost all systems in the universe. Unlike equilibrium systems, they interfere with their surroundings which results in never ceasing uxes. There is no unified theory to understand these ... -
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 ... -
Calculation of masses of dark solitons in 1D Bose-Einstein condensates using Gelfand Yaglom method
(Bilkent University, 2016-11)Nonlinear excitations of Bose-Einstein condensates (BEC) play important role in understanding the dynamics of BECs. Solitons, shape preserving wave packets, are the most fundamental nonlinear excitations of BECs. They ... -
Novel approaches to ultrafast fiber laser design for ablation-cooled material removal
(Bilkent University, 2016-11)The past few decades in particular have witnessed the tremendous beneficial impact of innovations in laser technology ranging from biomedical to industrial applications in response to enhancing community's quality of life. ... -
Graphene-based electrically tunable terahertz optoelectronics
(Bilkent University, 2016-11)Advances in terahertz (THz) research and technology, has bridged the gap between radio-frequency electronics and optics. More efficient control of THz waves would highly benefit noninvasive, high-resolution imaging ... -
Non-boltzmann stationary distributions and non-equilibrium relations in active baths
(Bilkent University, 2016-10)Most natural and engineered processes, such as biomolecular reactions, protein folding, and population dynamics, occur far from equilibrium and, therefore, can- not be treated within the framework of classical equilibrium ...
