Browsing by Author "Yurdasan, Nazli Boz"

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Ab Initio Calculations of Structural, Electronic, Elastic, Optical, and Dynamical Properties of Half-Heusler Lisib Compound
(Springer, 2022) Akyuz, Gonul Bilgec; Dogan, Emel Kilit; Yurdasan, Nazli Boz; Tunali, Aylin Yildiz; Gulebaglan, Sinem Erden
Structural, electrical, elastic, optical, and dynamical properties of LiSiB half-Heusler compound were analyzed based on density functional theory implemented in Quantum Espresso and ABINIT package programs. The effects of exchange-correlation interactions are handled by the generalized gradient approximation with Perdew-Burke-Ernzerhof parametrization. Firstly, the structure of this half-Heusler compound has been optimized and our results indicate that LiSiB reveals semiconducting behavior with an indirect band gap of 0.21 eV. The elastic constants, and other elastic modules have been computed. The mechanical stabilities of these alloys have been theoretically confirmed. The phonon dispersion spectra and phonon density of states in the Brillouin zone have been obtained and discussed. Also, the optical properties were calculated, and the results showed that the LiSiB alloy has a strong optical transition and the LiSiB crystal could be used in the design of optoelectronic devices. There are no results found on elastic, optical, and phonon features of LiSiB in the literature; hence, the findings reported here shed light on future studies.
The Effect of Disorder on Local Electron Temperature in Quantum Hall Systems
(Springer, 2021) Yurdasan, Nazli Boz; Gulebaglan, Sinem Erden; Siddiki, Afif
The local electron temperature distribution is calculated considering a two dimensional electron system in the integer quantum Hall regime in presence of disorder and uniform perpendicular magnetic fields. We solve thermo-hydrodynamic equations to obtain the spatial distribution of the local electron temperature in the linear-response regime. It is observed that, the variations of electron temperature exhibit an antisymmetry regarding the center of the sample in accordance with the location of incompressible strips. To understand the effect of sample mobility on the local electron temperature we impose a disorder potential calculated within the screening theory. Here, long range potential fluctuations are assumed to simulate cumulative disorder potential depending on the impurity atoms. We observe that the local electron temperature strongly depends on the number of impurities in narrow samples.Graphic abstractThe electron temperature Te versus position calculated for different values of the modulation potential V0. The calculations are done at TL=0.04EF0/kB lattice temperature considering impurity Nl=6600 and repeated for three different values of magnetic field omega c/EF0=0.80, 0.85 and 0.90. The insets show the enlarged region for the left side.