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Topological aspects of charge transport in quantum manybody systems
(Bilkent University, 201902)Motivated by the recent proposals and developments of topological insulators and topological superconductors for their potential applications in electronic devices and quantum computing, we have theoretically studied ... 
Haldane phase in the bondalternating spin1/2 XXZ chain: DMRG and fermionization studies
(Bilkent University, 201901)In this thesis, the subject of study is the Haldane phase in bond  alternating XXZ chain with S =1/2. We firstly mapped our model to the fermionic chain by the use of standard JordanWigner Transformation, which leads ... 
Novel concepts in high power semiconductor lasers
(Bilkent University, 201812)This doctoral thesis deals with innovations to the cavity optics of high power semiconductor lasers emitting light at 9xx nm. High power laser diodes are complex electronic and photonic systems. Developments in epitaxial ... 
Ground state energy of the fröhlich polaron as a function of dimensionality and the phonon coupling strength
(Bilkent University, 201809)We use the trial polaron wave function introduced by Devreese et al. [1] to estimate the ground state energies of the Fröhlich polaron over a broad range of the phonon coupling strength by a variational approach. We ... 
Investigation of thermoelectric properties of 2D βsilicon monotelluride (site)
(Bilkent University, 201809)Thermoelectric properties of novel 2D silicon monotelluride (SiTe) are studied using first principles calculations. The plane wave method based on density functional theory as implemented in Vienna ab initio simulation ... 
Optical and thermal dynamics of long wave quantum cascade lasers
(Bilkent University, 201809)Quantum Cascade Lasers (QCLs) are coherent light sources that make use of intraband transitions of wavefunction engineered semiconductor quantum wells. They have been designed to emit light in a wide spectral range; from ... 
Largescale semiempirical pseudopotential electronic structure of selfassembled ingaas quantum dots
(Bilkent University, 201809)The socalled second quantum revolution emerged at the beginning of the second millennium, opening up a path to realization of spinqubitbased quantum computing by means of controlling and protecting quantum coherent ... 
Variational study of interacting suschriefferheeger model
(Bilkent University, 201809)The interacting SuSchriefferHeeger model with nearest neighbor interaction in one dimension at halffilling is studied. To obtain ground state wave function, the Baeriswyl variational wave function is extended to account ... 
Electrostatic correlations in inhomogeneous electrolytes
(Bilkent University, 201808)The fieldtheoretic approach is used to obtain the selfconsistent equations for inhomogeneuos symmetric electrolytes. The perturbative Green's function method is used to solve these selfconsistent equations for an ... 
Gravitational waves from binary black hole systems in inspiralling phase
(Bilkent University, 201807)Binary black hole systems have three phases: inspiralling, merger and ringdown phases. This thesis is a review of methods developed to study the inspiralling phase analytically. Those methods include post Minkowskian ... 
Hyperfine and electric quadrupolar interactiondriven loschmidt echo in nanoscale nuclear spin baths
(Bilkent University, 201807)Environmental dynamics in solid state matrix is of much importance for quantum information processing and storage purposes. Here, we first give a basic recipe to get Loschmidt echo (LE) which is a measure of decoherence ... 
Sonic Hawking Radiation from a blackhole laser
(Bilkent University, 201806)The quantum thermal radiation from a black hole (BH) known as “Hawking Radiation” or “Black Hole Evaporation” results from studying quantum fields in the curved spacetime of the horizon of a BH. Experimentally, the ... 
The adiabatic and nonadiabatic behavior of a particle in optical lattices
(Bilkent University, 201806)The cold atom experiments provide a clean and controlled environment for realizing many body systems. Recent realizations of artificial gauge fields and adjustable optical lattices paved the way for the study of effectively ... 
Investigation of optical residual absorption in graphene
(Bilkent University, 201803)Graphene, a 2dimensional 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, 201802)It has been two decades since the quantumcascade 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, 201801)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, 200207)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 quasitwo dimensional materials
(Bilkent University, 201710)Since the advent of graphene, twodimensional (2D) materials have consistently been studied owing to their exceptional electronic and optical properties. While graphene is completely twodimensional in nature, its other ... 
Unconventional superconductivity in two dimensional time reversal symmetric noncentrosymmetric superconductors
(Bilkent University, 201709)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 (Θphase). The lack of ... 
Size controlled germanium nanocrystals in dielectrics : structural and optical analysis and stress evolution
(Bilkent University, 201709)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 ...