• Stress-energy connection: Degravitating the vacuum energy 

  Demir, Durmuş Ali (World Scientific Publishing, 2013)

  This talk summarizes recent studies on the gravitational properties of vacuum energy in a non-Riemannian geometry formed by the stress-energy tensor of vacuum, matter and radiation. Postulating that the gravitational effects ...

• Conductance fluctuations in undoped hydrogenated amorphous silicon-germanium alloy thin films 

  Güneş, Mehmet; Johanson, Robert E.; Kasap, Safa O.; Yang, Jeffrey C.; Guha, Subhendu (Elsevier, 2002-04)

  We report coplanar conductance fluctuations of device quality, undoped hydrogenated amorphous silicon-germanium alloy thin films (a-SiGe:H) measured from 430 to 490 K. The a-SiGe:H alloys produce noise power spectra similar ...

• Correlation of tunneling spectra in Bi2Sr2CaCu2O8+δ with the resonance spin excitation 

  Zasadzinski, John F.; Özyüzer, Lütfi; Miyakawa, Nobuaki; Gray, Kenneth E.; Hinks, David G.; Kendziora, Christopher A. (American Physical Society, 2001-08)

  New break-junction tunneling data are reported in Bi2Sr2CaCu2O8+δ over a wide range of hole concentration from underdoped (Tc=74k) to optimal doped (Tc=95k) to overdoped (Tc=48k). The conductances exhibit sharp dips at a ...

• Comparision of in situ spectroscopic ellipsometer and ex situ x-ray photoelectron spectroscopy depth profiling analysis of HfO2/Hf/Si multilayer structure 

  Cantaş, Ayten; Özyüzer, Lütfi; Aygün, Gülnur (Institute of Physics Publishing, 2018-09)

  A HfO2 film was grown by RF magnetron sputtering technique on a Si substrate Using in situ Spectroscopic Ellipsometry (SE), the film thickness and refractive index were examined as a function of deposition time. Ex situ ...

• Structural, electronic and phononic properties of PtSe2: From monolayer to bulk 

  Kandemir, Ali; Akbalı, Barış; Kahraman, Z.; Badalov, S. V.; Özcan, Mehmet; İyikanat, Fadıl; Şahin, Hasan (Institute of Physics Publishing, 2018-06)

  The layer dependent structural, electronic and vibrational properties of the 1T phase of two dimensional (2D) platinum diselenide are investigated by means of state-of-the-art first-principles calculations. The main findings ...

• Importance of CdS buffer layer thickness on Cu2ZnSnS4-based solar cell efficiency 

  Cantaş, Ayten; Türkoğlu, Fulya; Meriç, Ece; Akça, Fatime Gülşah; Özdemir, Mehtap; Tarhan, Enver; Özyüzer, Lütfi; Aygün, Gülnur (Institute of Physics Publishing, 2018-06)

  Cu2ZnSnS4 (CZTS) thin films were grown on Mo-coated soda lime glass (SLG) substrates by the sulfurization of DC magnetron-sputtered Zn, Sn and Cu metallic precursors under a sulfur atmosphere at 550 °C for 45 min. Understanding ...

• Wigner crystallization in topological flat bands 

  Jaworowski, Błażej; Güçlü, Alev Devrim; Kaczmarkiewicz, Piotr; Kupczyński, Michał; Potasz, Paweł; Wójs, Arkadiusz (Institute of Physics Publishing, 2018-06)

  We study the Wigner crystallization on partially filled topological flat bands of kagome, honeycomb and checkerboard lattices. We identify the Wigner crystals (WCs) by analyzing the Cartesian and angular Fourier transform ...

• The effect of atmospheric gases on the electrical stability of graphene 

  Kalkan, Sırrı Batuhan (Izmir Institute of Technology, 2017-12)

  In this thesis, adsorbate induced variations in the electrical conductivity of graphene layers with two different types of charge carriers are investigated experimentally by using Transient Photocurrent Spectroscopy (TPS) ...

• Comparison of photocatalytic properties of TiO2 thin films and fibers 

  Özdemir, Mehtap; Kurt, Metin; Özyüzer, Lütfi; Aygün, Gülnur (EDP Sciences, 2016-09)

  Efficiency of solar panels degrades as a result of organic contamination such as airborne particles, bird droppings and leaves. Any foreign object on photovoltaic panels reduces the sunlight entering the absorbing surface ...

• Softly fine-tuned Standard Model and the scale of inflation 

  Korutlu, Beste (World Scientific Publishing, 2015-11)

  The direct coupling between the Higgs field and the spacetime curvature, if finely tuned, is known to stabilize the Higgs boson mass. The fine-tuning is soft because the Standard Model (SM) parameters are subject to no ...

• Graphene-based integrated electronic, photonic and spintronic circuit 

  Potasz, P.; Güçlü, Alev Devrim; Özfidan, Işıl; Korkusinski, Marek; Hawrylak, Pawel (SPIE, 2013)

  To create carbon-based nanoscale integrated electronic, photonic, and spintronic circuit one must demonstrate the three functionalities in a single material, graphene quantum dots (GQDs), by engineering lateral size, shape, ...

• Semiclassical black holes with large N rescaling and information loss problem 

  Yeom, Dong-Han; Zoe, Heeseung (World Scientific Publishing, 2011-07)

  We consider semiclassical black holes and related rescalings with N massless fields. For a given semiclassical solution of an N = 1 universe, we can find other solution of a large N universe by the rescaling. After the ...

• Hydrogen-induced sp2-sp3 rehybridization in epitaxial silicene 

  Solonenko, Dmytro; Dzhagan, Volodymyr; Cahangirov, Seymur; Bacaksız, Cihan; Şahin, Hasan; Zahn, Dietrich R. T.; Vogt, Patrick (American Physical Society, 2017-12)

  We report on the hydrogenation of (3×3)/(4×4) silicene epitaxially grown on Ag(111) studied by in situ Raman spectroscopy and state-of-the-art ab initio calculations. Our results demonstrate that hydrogenation of (3×3)/(4×4) ...

• S- and T-self-dualities in dilatonic f(R) theories 

  Rador, Tonguç (Springer, 2017-12)

  We search for theories, in general spacetime dimensions, that would incorporate a dilaton and higher powers of the scalar Ricci curvature such that they have exact S- or T-self-dualities. The theories we find are free of ...

• Hydrogenation-driven phase transition in single-layer TiSe2 

  İyikanat, Fadıl; Kandemir, Ali; Özaydın, H. Duygu; Senger, Ramazan Tuğrul; Şahin, Hasan (IOP Publishing, 2017-11)

  First-principles calculations based on density-functional theory are used to investigate the effects of hydrogenation on the structural, vibrational, thermal and electronic properties of the charge density wave (CDW) phase ...

• Stable ultra-thin CdTe crystal: A robust direct gap semiconductor 

  İyikanat, Fadıl; Akbalı, Barış; Kang, J.; Senger, Ramazan Tuğrul; Selamet, Yusuf; Şahin, Hasan (IOP Publishing, 2017-11)

  Employing density functional theory based calculations, we investigate structural, vibrational and strain-dependent electronic properties of an ultra-thin CdTe crystal structure that can be derived from its bulk counterpart. ...

• Statistical approach to tunneling time in attosecond experiments 

  Demir, Durmuş Ali; Güner, Tuğrul (Elsevier, 2017-11)

  Tunneling, transport of particles through classically forbidden regions, is a pure quantum phenomenon. It governs numerous phenomena ranging from single-molecule electronics to donor–acceptor transition reactions. The main ...

• Electronic structure of cyanocobalamin: DFT+QMC study 

  Mayda, Selma; Kandemir, Zafer; Bulut, Nejat (Springer, 2017-11)

  We study the electronic structure and the magnetic correlations of cyanocobalamin (C63H88CoN14O14P) by using the framework of the multi-orbital single-impurity Haldane-Anderson model of a transition metal impurity in a ...

• Investigation of electron beam lithography effects on metal-insulator transition behavior of vanadium dioxide 

  Yüce, Hürriyet; Alaboz, Hakan; Demirhan, Yasemin; Özdemir, M.; Özyüzer, Lütfi; Aygün, Gülnur (IOP Publishing, 2017-10)

  Vanadium dioxide (VO2) shows metal-insulator phase transition at nearly 68 °C. This metal-insulator transition (MIT) in VO2 leads to a significant change in near-infrared transmittance and an abrupt change in the resistivity ...

• Thinning CsPb2Br5 perovskite down to monolayers: Cs-dependent stability 

  İyikanat, Fadıl; Sarı, Emre; Şahin, Hasan (American Physical Society, 2017-10)

  Using first-principles density functional theory calculations, we systematically investigate the structural, electronic, and vibrational properties of bulk and potential single-layer structures of perovskitelike CsPb2Br5 ...

View more