Browsing by Author "Kilit Dogan, Emel"

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Investigation of Structural, Electronic, Optic and Elastic Properties of Perovskite Rbgecl3 Crystal: a First Principles Study
(Gazi Univ, 2019) Erdinc, Fatma; Kilit Dogan, Emel; Akkus, Harun
Some physical properties of RbGeCl3 crystal are investigated with ABINIT computer program within the generalized gradient approximation (GGA) and the local density approximation (LDA), using density functional theory (DFT). We studied the geometry optimization, electronic band structure, electron density of states, optical properties such as the dielectric functions, reflectivity, refractive index, extinction coefficients, energy-loss functions for volume, the effective number of valence electrons per unit cell and elastic properties of RbGeCl3. The calculated electronic band structure shows that the RbGeCl3 has a direct band gap and this compound is a semiconducting material with a wide bandgap.
Tricritical Behavior of the Smectic-Hexatic Phase Transitions in Binary Mixtures Using the Landau Mean Field Theory
(Taylor & Francis Ltd, 2023) Yurtseven, Hamit; Kilit Dogan, Emel
The smectic-hexatic phase transitions are studied by the Landau mean field theory in binary mixtures, particularly, THI-14 + MPR-6 liquid crystalline system. By considering the phase lines of SmA-Hex B, SmC-SmF (Hex F) and SmF-Hex B as the first order; SmA-SmC and SmC-SmF as the second order, in the presence of the two tricritical points (C-F-B and A-C-B), we calculate the T-X phase diagram of the binary mixture studied. The phase line equations obtained from the free energies of the smectic and hexatic phases, are fitted to the experimental data given in the literature.We find that the Landau mean field theory explains satisfactorily the observed T-X phase diagram for the smectic-hexatic transitions in the binary mixture of THI-14 + MPR-6.