@article{13520, abstract = {{Atomistic simulations in the framework of the density functional theory have been used to model morphologic and vibrational properties of lithium niobate–lithium tantalate mixed crystals as a function of the [Nb]/[Ta] ratio. Structural parameters such as the crystal volume and the lattice parameters a and c vary roughly linearly from LiTaO3 to LiNbO3, showing only minor deviations from the Vegard behavior. Our ab initio calculations demonstrate that the TO1, TO2 and TO4 vibrational modes become harder with increasing Nb concentration. TO3 becomes softer with increasing Nb content, instead. Furthermore, the investigated zone center A1 -TO phonon modes are characterized by a pronounced stoichiometry dependence. Frequency shifts as large as 30 cm−1 are expected as the [Nb]/[Ta] ratio grows from 0 to 1. Therefore, spectroscopic techniques sensitive to the A1 modes (such as Raman spectroscopy), can be employed for a direct and non-destructive determination of the crystal composition.}}, author = {{Sanna, Simone and Riefer, A. and Neufeld, Sergej and Schmidt, Wolf Gero and Berth, Gerhard and Rüsing, Michael and Widhalm, A. and Zrenner, Artur}}, issn = {{0015-0193}}, journal = {{Ferroelectrics}}, keywords = {{Ferroelectrics, vibrational properties, LiNbO3, LiTaO3, mixed crystals}}, number = {{1}}, pages = {{63--68}}, title = {{{Vibrational Fingerprints of LiNbO3-LiTaO3Mixed Crystals}}}, doi = {{10.1080/00150193.2013.821893}}, volume = {{447}}, year = {{2013}}, } @article{13524, author = {{Landmann, M. and Rauls, E. and Schmidt, Wolf Gero and Röppischer, Marcus and Cobet, Christoph and Esser, Norbert and Schupp, Thorsten and As, Donat J. and Feneberg, Martin and Goldhahn, Rüdiger}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{19}}, title = {{{Transition energies and direct-indirect band gap crossing in zinc-blende AlxGa1−xN}}}, doi = {{10.1103/physrevb.87.195210}}, volume = {{87}}, year = {{2013}}, } @article{13517, author = {{Jesser, Anton and Rohrmüller, Martin and Schmidt, Wolf Gero and Herres-Pawlis, Sonja}}, issn = {{0192-8651}}, journal = {{Journal of Computational Chemistry}}, number = {{1-2}}, pages = {{1--17}}, title = {{{Geometrical and optical benchmarking of copper guanidine-quinoline complexes: Insights from TD-DFT and many-body perturbation theory†}}}, doi = {{10.1002/jcc.23449}}, volume = {{35}}, year = {{2013}}, } @article{13521, author = {{Sanna, S. and Rode, S. and Hölscher, R. and Klassen, S. and Marutschke, C. and Kobayashi, K. and Yamada, H. and Schmidt, Wolf Gero and Kühnle, A.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, title = {{{Charge compensation by long-period reconstruction in strongly polar lithium niobate surfaces}}}, doi = {{10.1103/physrevb.88.115422}}, volume = {{88}}, year = {{2013}}, } @article{13523, author = {{Longo, Roberto C. and Cho, Kyeongjae and Schmidt, Wolf Gero and Chabal, Yves J. and Thissen, Peter}}, issn = {{1616-301X}}, journal = {{Advanced Functional Materials}}, pages = {{3471--3477}}, title = {{{Monolayer Doping via Phosphonic Acid Grafting on Silicon: Microscopic Insight from Infrared Spectroscopy and Density Functional Theory Calculations}}}, doi = {{10.1002/adfm.201202808}}, volume = {{23}}, year = {{2013}}, } @article{13522, author = {{Aldahhak, Hazem and Schmidt, Wolf Gero and Rauls, E.}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{242--248}}, title = {{{Adsorption of PTCDA on NaCl(100) and KCl(100)}}}, doi = {{10.1016/j.susc.2013.08.003}}, volume = {{617}}, year = {{2013}}, } @article{13518, author = {{Frigge, T. and Wall, S. and Krenzer, B. and Wippermann, St. and Sanna, S. and Klasing, F. and Hanisch-Blicharski, A. and Kammler, M. and Schmidt, Wolf Gero and Horn-von Hoegen, M.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, pages = {{149602}}, title = {{{Friggeet al.Reply:}}}, doi = {{10.1103/physrevlett.111.149602}}, volume = {{111}}, year = {{2013}}, } @article{13519, author = {{Riefer, A. and Sanna, S. and Schmidt, Wolf Gero}}, issn = {{0015-0193}}, journal = {{Ferroelectrics}}, pages = {{78--85}}, title = {{{LiNb1-xTaxO3Electronic Structure and Optical Response fromFirst-PrinciplesCalculations}}}, doi = {{10.1080/00150193.2013.821904}}, volume = {{447}}, year = {{2013}}, } @article{13528, author = {{George, B. M. and Behrends, J. and Schnegg, A. and Schulze, T. F. and Fehr, M. and Korte, L. and Rech, B. and Lips, K. and Rohrmüller, M. and Rauls, E. and Schmidt, Wolf Gero and Gerstmann, Uwe}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{13}}, title = {{{Atomic Structure of Interface States in Silicon Heterojunction Solar Cells}}}, doi = {{10.1103/physrevlett.110.136803}}, volume = {{110}}, year = {{2013}}, } @article{13527, author = {{Rohrmüller, M. and Herres-Pawlis, S. and Witte, M. and Schmidt, Wolf Gero}}, issn = {{0192-8651}}, journal = {{Journal of Computational Chemistry}}, pages = {{1035--1045}}, title = {{{Bis-μ-oxo and μ-η2:η2-peroxo dicopper complexes studied within (time-dependent) density-functional and many-body perturbation theory}}}, doi = {{10.1002/jcc.23230}}, volume = {{34}}, year = {{2013}}, } @article{13525, abstract = {{The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe-Salpeter equation for the stoichiometric material yield a dielectric function that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are, at least, partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that the inclusion of self-energy effects in the nonlinear optical response leads to a better agreement with experiments. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular, for the 21 and 31 tensor components, further improving the agreement between experiments and theory.}}, author = {{Riefer, Arthur and Sanna, Simone and Schindlmayr, Arno and Schmidt, Wolf Gero}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{19}}, publisher = {{American Physical Society}}, title = {{{Optical response of stoichiometric and congruent lithium niobate from first-principles calculations}}}, doi = {{10.1103/PhysRevB.87.195208}}, volume = {{87}}, year = {{2013}}, } @article{13526, author = {{Eberhard, Jens and Stoll, Ion and Brockhinke, Regina and Neumann, Beate and Stammler, Hans-Georg and Riefer, Arthur and Rauls, Eva and Schmidt, Wolf Gero and Mattay, Jochen}}, issn = {{1466-8033}}, journal = {{CrystEngComm}}, number = {{21}}, title = {{{Structural variety of 5-fluoroarene-2-aminopyrimidine in comparison to 2-aminopyrimidine silver(i) coordination polymers: progress report and overview}}}, doi = {{10.1039/c2ce26388b}}, volume = {{15}}, year = {{2013}}, } @article{13819, author = {{Riefer, A. and Sanna, S. and Schmidt, Wolf Gero}}, issn = {{0015-0193}}, journal = {{Ferroelectrics}}, pages = {{78--85}}, title = {{{LiNb1-xTaxO3Electronic Structure and Optical Response fromFirst-PrinciplesCalculations}}}, doi = {{10.1080/00150193.2013.821904}}, volume = {{447}}, year = {{2013}}, } @inbook{18475, abstract = {{The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the GW approximation to account for quasiparticle effects and the solution of the Bethe–Salpeter equation yield a dielectric function for the stoichiometric material that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are at least partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that self-energy effects improve the agreement between experiment and theory. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular for the 21 and 31 tensor components, further improving the agreement with measured data.}}, author = {{Riefer, Arthur and Rohrmüller, Martin and Landmann, Marc and Sanna, Simone and Rauls, Eva and Vollmers, Nora Jenny and Hölscher, Rebecca and Witte, Matthias and Li, Yanlu and Gerstmann, Uwe and Schindlmayr, Arno and Schmidt, Wolf Gero}}, booktitle = {{High Performance Computing in Science and Engineering ‘13}}, editor = {{Nagel, Wolfgang E. and Kröner, Dietmar H. and Resch, Michael M.}}, isbn = {{978-3-319-02164-5}}, pages = {{93--104}}, publisher = {{Springer}}, title = {{{Lithium niobate dielectric function and second-order polarizability tensor from massively parallel ab initio calculations}}}, doi = {{10.1007/978-3-319-02165-2_8}}, year = {{2013}}, } @article{13546, author = {{Riefer, A. and Rauls, E. and Schmidt, Wolf Gero and Eberhard, J. and Stoll, I. and Mattay, J.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{16}}, title = {{{2-Aminopyrimidine-silver(I) based organic semiconductors: Electronic structure and optical response}}}, doi = {{10.1103/physrevb.85.165202}}, volume = {{85}}, year = {{2012}}, } @article{13545, author = {{Landmann, M and Rauls, E and Schmidt, Wolf Gero}}, issn = {{0953-8984}}, journal = {{Journal of Physics: Condensed Matter}}, title = {{{The electronic structure and optical response of rutile, anatase and brookite TiO2}}}, doi = {{10.1088/0953-8984/24/19/195503}}, volume = {{24}}, year = {{2012}}, } @article{13548, author = {{Thissen, Peter and Thissen, Vera and Wippermann, Stefan and Chabal, Yves J. and Grundmeier, Guido and Schmidt, Wolf Gero}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{902--907}}, title = {{{pH-dependent structure and energetics of H2O/MgO(100)}}}, doi = {{10.1016/j.susc.2012.01.018}}, volume = {{606}}, year = {{2012}}, } @article{13542, author = {{Thissen, Peter and Peixoto, Tatiana and Longo, Roberto C. and Peng, Weina and Schmidt, Wolf Gero and Cho, Kyeongjae and Chabal, Yves J.}}, issn = {{0002-7863}}, journal = {{Journal of the American Chemical Society}}, pages = {{8869--8874}}, title = {{{Activation of Surface Hydroxyl Groups by Modification of H-Terminated Si(111) Surfaces}}}, doi = {{10.1021/ja300270w}}, volume = {{134}}, year = {{2012}}, } @article{13543, author = {{Rauls, E. and Schmidt, Wolf Gero and Pertram, T. and Wandelt, K.}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{1120--1125}}, title = {{{Interplay between metal-free phthalocyanine molecules and Au(110) substrates}}}, doi = {{10.1016/j.susc.2012.03.010}}, volume = {{606}}, year = {{2012}}, } @article{13560, author = {{Hölscher, R. and Sanna, S. and Schmidt, Wolf Gero}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{6}}, pages = {{1361--1365}}, title = {{{Adsorption of OH and H at the LiNbO3(0001) surface}}}, doi = {{10.1002/pssc.201100534}}, volume = {{9}}, year = {{2012}}, }