https://hdl.handle.net/20.500.12619/3349 2026-04-06T02:26:21Z https://hdl.handle.net/20.500.12619/32347 Electronic and vibrational properties of the GaSb(110) surface Tütüncü, Hüseyin Murat Results of ab initio pseudopotential calculations for atomic geometry and electronic band structure of the GaSb(110) surface are presented and discussed. The calculated atomic geometry is in good agreement with low-energy electron diffraction analysis. Our electronic structure agrees very well with angle-resolved photoemission measurements. The relaxed atomic geometry is used for calculations of the surface phonon modes within the adiabatic bond-charge model. The calculated phonon spectrum compares very well with the data obtained in a recent high-resolution electron energy-loss spectroscopy experiment. We also provide an analysis of the polarisation characteristics of important surface phonon modes. (C) 1999 Elsevier Science B.V. All rights reserved. 1999-01-01T00:00:00Z https://hdl.handle.net/20.500.12619/32325 Surface phonons on Si(001)/As(2x1) Tütüncü, Hüseyin Murat We present results of phonon calculations for the Si(001)/As(2x1) surface using the adiabatic bond-charge model. It is found that this surface is characterized by two pronounced peaks in the phonon density of states. One of these lies below the bulk continuum at the zone edges and is due to surface acoustic waves involving vibrations of the As atoms. The second of these lies at the bulk acoustic-optical boundary and is related to the vibrations of the symmetric As-As dimer against the substrate. (C) 1999 Elsevier Science B.V. All rights reserved. 1999-01-01T00:00:00Z https://hdl.handle.net/20.500.12619/32267 Surface dynamics of AlSb(110) and GaP(110) Tütüncü, Hüseyin Murat We have investigated the lattice dynamics of the (110) surface of AlSb and GaP by employing the adiabatic bond-charge model and using the atomic geometry obtained from ab initio pseudopotential calculations. The results for both surfaces are in very good overall agreement with a recent high-resolution electron-energy-loss spectroscopy experiment and an ab initio calculation. The differences between the dynamical properties of these surfaces are correlated to the cation/anion mass ratios. (C) 1999 Elsevier Science B.V. Ail rights reserved. 1999-01-01T00:00:00Z https://hdl.handle.net/20.500.12619/32199 AIP Conference Proceedings Aynur Kilicarslan; Ece Bal; Mustafa Dinc; Bahadir Salmankurt; Duman, Sıtkı; B Akkus; Y Oktem; Ls Yalcin; Rbc Mutlu; Gs Dogan We have employed the ab initio pseudopotential method, within a generalized gradient approximation of the density functional theory, a linear response approach, to determine atomic, elastic and lattice dynamical properties of the BaNbO3. The obtained structural and elastic parameter are in good agreement with previous experimental and theoretical results. The analysis of B/G ratio indicates that BaNbO3 is a ductile material. The calculated lattice dynamical properties compared with phonon spectrum of the similar structures. 2016-01-01T00:00:00Z