Browsing by Subject "Mechanical and electronic properties"

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Open Access
Electronic structure of conventional slater type antiferromagnetic insulators: AIrO3 (A=Sr, Ba) perovskites
(Institute of Physics, 2022) Koc, Husnu; Mamedov, Amirullah M.; Özbay, Ekmel
The structural, mechanical, and electronic properties of Perovskite BaIrO3 and SrIrO3 compounds based on the density functional theory (DFT) have been examined in four different structures (C2/c, R-3m, P6_3/mmc and Pm-3m) and Pnma structure, respectively. The spin polarized generalized gradient approximation has been used for modeling exchange-correlation effects. As a result of spin polarized calculations, it has been observed that BaIrO3 compound showed magnetic properties in C2/c and R-3m structures, but not in Pm-3m and P6_3/mmc structures. SrIrO3 compound also shows magnetic properties in Pnma structure. The elastic constants have been calculated using the strain-stress method and the other related quantities (the bulk modulus, shear modulus, Young's modulus, Poisson's ratio, anisotropy factor, sound velocities, and Debye temperature) have also been estimated. In electronic band structure calculations, while Pm-3m and P6_3/mmc structures of NaIrO3 compound are metallic and semiconductor (Eg = 1.190 eV indirect), respectively, while C2/c and R-3m structures showing magnetic properties are metallic in spin down state and semiconductor (Eg=0.992 eV indirect and Eg=0.665 eV direct, respectively) in the spin up state. The Pmna structure in the SrIrO3 compound is a semiconductor in both spin states (Eg=0.701 eV “0.632 eV” indirect in the spin up “spin down”). © 2022 Institute of Physics Publishing. All rights reserved.
Open Access
Polymeric nanofibers decorated with reduced graphene oxide nanoflakes
(Elsevier, 2017) Ranjith, K. S.; Uyar, Tamer
Research into graphene-polymeric based membranes by tuning its structural and functional properties will facilitate new opportunities on these hierarchical platforms. The objective is to play a role on the external skin of the polymeric nanofibers to enhance it structural and functional properties by introducing thin layered graphene oxide flakes to improve the absorption behavior, and to modulate the mechanical and electronic properties and more. By modifying the polymers and including some metal nanostructures within the graphene functionality may lead to the development of complex hybrid system for advanced applicability in fields such as catalyst, electronics, sensing, storage based devices, etc. Constructing the graphenebased systems with polymeric membranes having unique architecture and functionality will provide innovation in materials science in related fields. The hierarchical arrangement of reduced graphene oxide-polymeric membrane can play a key role in multifunctional application in the fields of electronics, catalysts, and sensors.
Open Access
The response of mechanical and electronic properties of graphane to the elastic strain
(AIP Publishing LLC, 2010) Topsakal, M.; Cahangirov, S.; Çıracı, Salim
Based on first-principles calculations, we resent a method to reveal the elastic properties of recently synthesized monolayer hydrocarbon, graphane. The in-plane stiffness and Poisson’s ratio values are found to be smaller than those of graphene, and its yielding strain decreases in the presence of various vacancy defects and also at high ambient temperature. We also found that the band gap can be strongly modified by applied strain in the elastic range.