@article{13837, abstract = {{In non-annealed 6H-SiC samples that were electron irradiated at room temperature, a new EPR signal due to a S=1 defect center with exceptionally large zero-field splitting (D = +652•10-4 cm-1) has been observed under illumination. A positive sign of D demonstrates that the spin-orbit contribution to the zero-field splitting exceeds by far that of the spin-spin interaction. A principal axis of the fine structure tilted by 59° against the crystal c-axis as well as the exceptionally high zero-field splitting D can be qualitatively understood by the occurrence of additional close-lying defect levels in defect clusters resulting in comparatively large second-order spin-orbit coup¬ling. A tentative assignment to vacancy clusters is supported by the observed annealing behavior. }}, author = {{Scholle, Andreas and Greulich-Weber, Siegmund and Rauls, Eva and Schmidt, Wolf Gero and Gerstmann, Uwe}}, issn = {{1662-9752}}, journal = {{Materials Science Forum}}, pages = {{403--406}}, title = {{{Fine Structure of Triplet Centers in Room Temperature Irradiated 6H-SiC}}}, doi = {{10.4028/www.scientific.net/msf.645-648.403}}, volume = {{645-648}}, year = {{2010}}, } @article{13843, author = {{Wippermann, S. and Schmidt, Wolf Gero and Thissen, P. and Grundmeier, Guido}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{137--140}}, title = {{{Dissociative and molecular adsorption of water onα-Al2O3(0001)}}}, doi = {{10.1002/pssc.200982423}}, volume = {{7}}, year = {{2010}}, } @article{13836, author = {{Rauls, E. and Blankenburg, S. and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{12}}, title = {{{Chemical reactivity on surfaces: Modeling the imide synthesis from DATP and PTCDA on Au(111)}}}, doi = {{10.1103/physrevb.81.125401}}, volume = {{81}}, year = {{2010}}, } @article{13842, author = {{Sanna, Simone and Gavrilenko, Alexander V. and Schmidt, Wolf Gero}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{145--148}}, title = {{{Ab initio investigation of the LiNbO3(0001) surface}}}, doi = {{10.1002/pssc.200982456}}, volume = {{7}}, year = {{2010}}, } @article{13841, author = {{Blankenburg, S. and Rauls, E. and Schmidt, Wolf Gero}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{153--156}}, title = {{{The physics of highly ordered molecular rows}}}, doi = {{10.1002/pssc.200982459}}, volume = {{7}}, year = {{2010}}, } @article{13835, author = {{Scholle, A. and Greulich-Weber, S. and As, Donat Josef and Mietze, Ch. and Son, N. T. and Hemmingsson, C. and Monemar, B. and Janzén, E. and Gerstmann, Uwe and Sanna, S. and Rauls, E. and Schmidt, Wolf Gero}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, number = {{7}}, pages = {{1728--1731}}, title = {{{Magnetic characterization of conductance electrons in GaN}}}, doi = {{10.1002/pssb.200983582}}, volume = {{247}}, year = {{2010}}, } @article{13831, author = {{Speiser, E. and Chandola, S. and Hinrichs, K. and Gensch, M. and Cobet, C. and Wippermann, S. and Schmidt, Wolf Gero and Bechstedt, F. and Richter, W. and Fleischer, K. and McGilp, J. F. and Esser, N.}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, number = {{8}}, pages = {{2033--2039}}, title = {{{Metal-insulator transition in Si(111)-(4 × 1)/(8 × 2)-In studied by optical spectroscopy}}}, doi = {{10.1002/pssb.200983961}}, volume = {{247}}, year = {{2010}}, } @article{13832, author = {{Thierfelder, C. and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{11}}, title = {{{First-principles study of water adsorption and a high-density interfacial ice structure on(1×1)-O/Rh(111)}}}, doi = {{10.1103/physrevb.82.115402}}, volume = {{82}}, year = {{2010}}, } @article{13829, author = {{Krivosheeva, A.V. and Sanna, S. and Schmidt, Wolf Gero}}, issn = {{0927-0256}}, journal = {{Computational Materials Science}}, number = {{4}}, pages = {{895--898}}, title = {{{First-principles investigation of CO adsorption on Pt/Ge(001)-(4×2)}}}, doi = {{10.1016/j.commatsci.2010.06.043}}, volume = {{49}}, year = {{2010}}, } @article{13827, author = {{Wippermann, S. and Schmidt, Wolf Gero}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{12}}, title = {{{Entropy Explains Metal-Insulator Transition of the Si(111)-In Nanowire Array}}}, doi = {{10.1103/physrevlett.105.126102}}, volume = {{105}}, year = {{2010}}, } @article{13828, author = {{Zirkelbach, F. and Stritzker, B. and Nordlund, K. and Lindner, J. K. N. and Schmidt, Wolf Gero and Rauls, E.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{9}}, title = {{{Defects in carbon implanted silicon calculated by classical potentials and first-principles methods}}}, doi = {{10.1103/physrevb.82.094110}}, volume = {{82}}, year = {{2010}}, } @article{13833, author = {{Sanna, Simone and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{21}}, title = {{{Lithium niobateX-cut,Y-cut, andZ-cut surfaces fromab initiotheory}}}, doi = {{10.1103/physrevb.81.214116}}, volume = {{81}}, year = {{2010}}, } @article{13830, author = {{Rauls, E. and Wiebe, J. and Schmidt, Wolf Gero}}, issn = {{0022-0248}}, journal = {{Journal of Crystal Growth}}, pages = {{2892--2895}}, title = {{{Understanding the cubic AlN growth plane from first principles}}}, doi = {{10.1016/j.jcrysgro.2010.07.027}}, volume = {{312}}, year = {{2010}}, } @article{13834, author = {{Sanna, Simone and Schmidt, Wolf Gero}}, issn = {{0169-4332}}, journal = {{Applied Surface Science}}, pages = {{5740--5743}}, title = {{{GaN/LiNbO3 (0001) interface formation calculated from first-principles}}}, doi = {{10.1016/j.apsusc.2010.03.098}}, volume = {{256}}, year = {{2010}}, } @article{13826, author = {{Blankenburg, S. and Rauls, E. and Schmidt, Wolf Gero}}, issn = {{1948-7185}}, journal = {{The Journal of Physical Chemistry Letters}}, pages = {{3266--3270}}, title = {{{Catalytic Action of a Cu(111) Surface on Tetraazaperopyrene Polymerization}}}, doi = {{10.1021/jz101389u}}, volume = {{1}}, year = {{2010}}, } @article{15846, author = {{Schumacher, Stefan and Galbraith, Ian and Ruseckas, Arvydas and Turnbull, Graham A. and Samuel, Ifor D. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, title = {{{Dynamics of photoexcitation and stimulated optical emission in conjugated polymers: A multiscale quantum-chemistry and Maxwell-Bloch-equations approach}}}, doi = {{10.1103/physrevb.81.245407}}, year = {{2010}}, } @article{18562, abstract = {{The structural and electronic properties of strained silicon are investigated quantitatively with ab initio computational methods. For this purpose we combine densityfunctional theory within the local‐density approximation and the GW approximation for the electronic self‐energy. From the variation of the total energy as a function of applied strain we obtain the elastic constants, Poisson ratios and related structural parameters, taking a possible internal relaxation fully into account. For biaxial tensile strain in the (001) and (111) planes we then investigate the effects on the electronic band structure. These strain configurations occur in epitaxial silicon films grown on SiGe templates along different crystallographic directions. The tetragonal deformation resulting from (001) strain induces a valley splitting that removes the sixfold degeneracy of the conduction‐band minimum. Furthermore, strain in any direction causes the band structure to warp. We present quantitative results for the electron effective mass, derived from the curvature of the conduction band, as a function of strain and discuss the implications for the mobility of the charge carriers. The inclusion of proper self‐energy corrections within the GW approximation in our work not only yields band gaps in much better agreement with experimental measurements than the localdensity approximation, but also predicts slightly larger electron effective masses.}}, author = {{Bouhassoune, Mohammed and Schindlmayr, Arno}}, issn = {{1610-1642}}, journal = {{Physica Status Solidi C}}, location = {{Weimar}}, number = {{2}}, pages = {{460--463}}, publisher = {{Wiley-VCH}}, title = {{{Electronic structure and effective masses in strained silicon}}}, doi = {{10.1002/pssc.200982470}}, volume = {{7}}, year = {{2010}}, } @inbook{18549, abstract = {{We describe the software package SPEX, which allows first-principles calculations of quasiparticle and collective electronic excitations in solids using techniques from many-body perturbation theory. The implementation is based on the full-potential linearized augmented-plane-wave (FLAPW) method, which treats core and valence electrons on an equal footing and can be applied to a wide range of materials, including transition metals and rare earths. After a discussion of essential features that contribute to the high numerical efficiency of the code, we present illustrative results for quasiparticle band structures calculated within the GW approximation for the electronic self-energy, electron-energy-loss spectra with inter- and intraband transitions as well as local-field effects, and spin-wave spectra of itinerant ferromagnets. In all cases the inclusion of many-body correlation terms leads to very good quantitative agreement with experimental spectroscopies.}}, author = {{Schindlmayr, Arno and Friedrich, Christoph and Şaşıoğlu, Ersoy and Blügel, Stefan}}, booktitle = {{Modern and Universal First-Principles Methods for Many-Electron Systems in Chemistry and Physics}}, editor = {{Dolg, Franz Michael}}, isbn = {{978-3-486-59827-8}}, pages = {{67--78}}, publisher = {{Oldenbourg}}, title = {{{First-principles calculation of electronic excitations in solids with SPEX}}}, doi = {{10.1524/9783486711639.67}}, volume = {{3}}, year = {{2010}}, } @article{18560, abstract = {{We present a computational scheme to study spin excitations in magnetic materials from first principles. The central quantity is the transverse spin susceptibility, from which the complete excitation spectrum, including single-particle spin-flip Stoner excitations and collective spin-wave modes, can be obtained. The susceptibility is derived from many-body perturbation theory and includes dynamic correlation through a summation over ladder diagrams that describe the coupling of electrons and holes with opposite spins. In contrast to earlier studies, we do not use a model potential with adjustable parameters for the electron-hole interaction but employ the random-phase approximation. To reduce the numerical cost for the calculation of the four-point scattering matrix we perform a projection onto maximally localized Wannier functions, which allows us to truncate the matrix efficiently by exploiting the short spatial range of electronic correlation in the partially filled d or f orbitals. Our implementation is based on the full-potential linearized augmented-plane-wave method. Starting from a ground-state calculation within the local-spin-density approximation (LSDA), we first analyze the matrix elements of the screened Coulomb potential in the Wannier basis for the 3d transition-metal series. In particular, we discuss the differences between a constrained nonmagnetic and a proper spin-polarized treatment for the ferromagnets Fe, Co, and Ni. The spectrum of single-particle and collective spin excitations in fcc Ni is then studied in detail. The calculated spin-wave dispersion is in good overall agreement with experimental data and contains both an acoustic and an optical branch for intermediate wave vectors along the [100] direction. In addition, we find evidence for a similar double-peak structure in the spectral function along the [111] direction. To investigate the influence of static correlation we finally consider LSDA+U as an alternative starting point and show that, together with an improved description of the Fermi surface, it yields a more accurate quantitative value for the spin-wave stiffness constant, which is overestimated in the LSDA.}}, author = {{Şaşıoğlu, Ersoy and Schindlmayr, Arno and Friedrich, Christoph and Freimuth, Frank and Blügel, Stefan}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{5}}, publisher = {{American Physical Society}}, title = {{{Wannier-function approach to spin excitations in solids}}}, doi = {{10.1103/PhysRevB.81.054434}}, volume = {{81}}, year = {{2010}}, } @article{18557, abstract = {{We describe the software package SPEX, which allows first-principles calculations of quasiparticle and collective electronic excitations in solids using techniques from many-body perturbation theory. The implementation is based on the full-potential linearized augmented-plane-wave (FLAPW) method, which treats core and valence electrons on an equal footing and can be applied to a wide range of materials, including transition metals and rare earths. After a discussion of essential features that contribute to the high numerical efficiency of the code, we present illustrative results for quasiparticle band structures calculated within the GW approximation for the electronic self-energy, electron-energy-loss spectra with inter- and intraband transitions as well as local-field effects, and spin-wave spectra of itinerant ferromagnets. In all cases the inclusion of many-body correlation terms leads to very good quantitative agreement with experimental spectroscopies.}}, author = {{Schindlmayr, Arno and Friedrich, Christoph and Şaşıoğlu, Ersoy and Blügel, Stefan}}, issn = {{2196-7156}}, journal = {{Zeitschrift für Physikalische Chemie}}, number = {{3-4}}, pages = {{357--368}}, publisher = {{Oldenbourg}}, title = {{{First-principles calculation of electronic excitations in solids with SPEX}}}, doi = {{10.1524/zpch.2010.6110}}, volume = {{224}}, year = {{2010}}, }