@article{13823, author = {{Sanna, S. and Berth, Gerhard and Hahn, W. and Widhalm, A. and Zrenner, Artur and Schmidt, Wolf Gero}}, issn = {{0885-3010}}, journal = {{IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control}}, number = {{9}}, pages = {{1751--1756}}, title = {{{Vibrational properties of the LiNbO3 z-surfaces}}}, doi = {{10.1109/tuffc.2011.2012}}, volume = {{58}}, year = {{2011}}, } @article{13824, 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 = {{6}}, title = {{{Combined ab initio and classical potential simulation study on silicon carbide precipitation in silicon}}}, doi = {{10.1103/physrevb.84.064126}}, volume = {{84}}, year = {{2011}}, } @article{4089, abstract = {{We study the influence of the phonon environment on the electron dynamics in a doped quantum dot molecule. A non-perturbative quantumkinetic theory based on correlation expansion is used in order to describe both diagonal and off-diagonal electron-phonon couplings representing real and virtual processes with relevant acoustic phonons. We show that the relaxation is dominated by phononassisted electron tunneling between constituent quantum dots and occurs on a picosecond time scale. The dependence of the time evolution of the quantum dot occupation probabilities on the energy mismatch between the quantum dots is studied in detail.}}, author = {{Grodecka-Grad, Anna and Förstner, Jens}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_qd}}, number = {{4}}, pages = {{1125--1128}}, publisher = {{Wiley}}, title = {{{Phonon-assisted decoherence and tunneling in quantum dot molecules}}}, doi = {{10.1002/pssc.201000824}}, volume = {{8}}, year = {{2011}}, } @article{4120, abstract = {{The intensity dependence of optically-induced injection currents in unbiased GaAs semiconductor quantum wells grown in [110] direction is investigated theoretically for a number of well widths. Our microscopic analysis is based on a 14 x 14 band k . p method in combination with the multisubband semiconductor Bloch equations. An oscillatory dependence of the injection current transients as function of intensity and time is predicted and explained. It is demonstrated that optical excitations involving different subbands and Rabi flopping are responsible for this complex dynamics.}}, author = {{Pochwała, Michał and Duc, Huynh Thanh and Förstner, Jens and Meier, Torsten}}, issn = {{1862-6254}}, journal = {{physica status solidi (RRL) - Rapid Research Letters}}, keywords = {{tet_topic_qw}}, number = {{3}}, pages = {{119--121}}, publisher = {{Wiley}}, title = {{{Intensity-dependent ultrafast dynamics of injection currents in unbiased GaAs quantum wells}}}, doi = {{10.1002/pssr.201004529}}, volume = {{5}}, year = {{2011}}, } @article{4049, abstract = {{The injection of photocurrents by femtosecond laser pulses in (110)-orientedGaAs/AlGaAs quantum wells is investigated theoretically and experimentally. The roomtemperature measurements show an oscillatory dependence of the injection current amplitude and direction on the excitation photon energy. Microscopic calculations using the semiconductor Bloch equations that are set up on the basis of k.p band structure calculations provide a detailed understanding of the experimental findings.}}, author = {{Thanh Duc, Huynh and Förstner, Jens and Meier, Torsten and Priyadarshi, Shekhar and Racu, Ana Maria and Pierz, Klaus and Siegner, Uwe and Bieler, Mark}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_qw}}, number = {{4}}, pages = {{1137--1140}}, publisher = {{Wiley}}, title = {{{Oscillatory excitation energy dependence of injection currents in GaAs/AlGaAs quantum wells}}}, doi = {{10.1002/pssc.201000831}}, volume = {{8}}, year = {{2011}}, } @article{4118, abstract = {{We numerically investigate the coupling between circular resonators and study strong light‐matter coupling of single as well as multiple circular resonators to quantum‐mechanical resonators in two dimensional model simulations. For all cases, the computed resonances of the coupled system as function of the detuning show anti‐crossings. The obtained mode splittings of coupled optical resonators are strongly depending on distance and cluster in almost degenerate eigenstates for large distances, as is known from coupled resonator optical waveguides. Vacuum Rabi splitting is observed for a quantum dot strongly coupled to eigenmodes of single perfectly cylindrical resonators. }}, author = {{Declair, S. and Meier, Torsten and Förstner, Jens}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_phc, tet_topic_microdisk}}, number = {{4}}, pages = {{1254--1257}}, publisher = {{Wiley}}, title = {{{Numerical investigation of the coupling between microdisk modes and quantum dots}}}, doi = {{10.1002/pssc.201000869}}, volume = {{8}}, year = {{2011}}, } @article{4040, abstract = {{We numerically investigate the interaction dynamics of coupled cavities in planar photonic crystal slabs in different configurations. The single cavity is optimized for a long lifetime of the fundamental mode, reaching a Q-factor of ≈43, 000 using the method of gentle confinement. For pairs of cavities we consider several configurations and present a setup with strongest coupling observable as a line splitting of about 30 nm. Based on this configuration, setups with three cavities are investigated.}}, author = {{Declair, S. and Meier, Torsten and Zrenner, Artur and Förstner, Jens}}, issn = {{1569-4410}}, journal = {{Photonics and Nanostructures - Fundamentals and Applications}}, keywords = {{tet_topic_phc}}, number = {{4}}, pages = {{345--350}}, publisher = {{Elsevier BV}}, title = {{{Numerical analysis of coupled photonic crystal cavities}}}, doi = {{10.1016/j.photonics.2011.04.012}}, volume = {{9}}, year = {{2011}}, } @article{4044, abstract = {{A simulation environment for metallic nanostructures based on the Discontinuous Galerkin Time Domain method is presented. The model is used to compute the linear and nonlinear optical response of split ring resonators and to study physical mechanisms that contribute to second harmonic generation.}}, author = {{Grynko, Yevgen and Förstner, Jens and Meier, Torsten}}, issn = {{1825-1242}}, journal = {{AAPP | Atti della Accademia Peloritana dei Pericolanti}}, keywords = {{tet_topic_numerics, tet_topic_shg, tet_topic_meta}}, number = {{1}}, title = {{{Application of the discontinous Galerkin time domain method to the optics of metallic nanostructures}}}, doi = {{10.1478/C1V89S1P041}}, volume = {{89}}, year = {{2011}}, } @article{4091, abstract = {{We present a nonequilibrium ab initio method for calculating nonlinear and nonlocal optical effects in metallic slabs with a thickness of several nanometers. The numerical analysis is based on the full solution of the time‐dependent Kohn–Sham equations for a jellium system and allows to study the optical response of metal electrons subject to arbitrarily shaped intense light pulses. We find a strong localization of the generated second‐harmonic current in the surface regions of the slabs. }}, author = {{Wand, Mathias and Schindlmayr, Arno and Meier, Torsten and Förstner, Jens}}, issn = {{1521-3951}}, journal = {{Physica Status Solidi B}}, keywords = {{tet_topic_shg}}, number = {{4}}, pages = {{887--891}}, publisher = {{Wiley-VCH}}, title = {{{Simulation of the ultrafast nonlinear optical response of metal slabs}}}, doi = {{10.1002/pssb.201001219}}, volume = {{248}}, year = {{2011}}, } @article{4543, abstract = {{The vibrational properties of the LiNbO3 (0001) surfaces have been investigated both from first principles and with Raman spectroscopy measurements. Firstly, the phonon modes of bulk and of the (0001) surface are calculated by means of the density functional theory. Our calculations reveal the existence of localised vibrational modes both at the positive and at the negative surface. The surface vibrations are found at energies above and within the bulk bands. Phonon modes localised at the positive and at the negative surface differ substantially. In a second step, the Raman spectra of LiNbO3 bulk and of the two surfaces have been measured. Raman spectroscopy is shown to be sensitive to differences between bulk and surface and between positive and negative surface. The calculated and measured frequencies are in agreement within the error of the method.}}, author = {{Sanna, S. and Berth, Gerhard and Hahn, W. and Widhalm, A. and Zrenner, Artur and Schmidt, Wolf Gero}}, issn = {{0015-0193}}, journal = {{Ferroelectrics}}, number = {{1}}, pages = {{1--8}}, publisher = {{Informa UK Limited}}, title = {{{Localised Phonon Modes at LiNbO3(0001) Surfaces}}}, doi = {{10.1080/00150193.2011.594396}}, volume = {{419}}, year = {{2011}}, } @inproceedings{4122, abstract = {{We experimentally and theoretically investigate injection currents generated by femtosecond single-color circularly-polarized laser pulses in (110)-oriented GaAs quantum wells. The current measurements are performed by detecting the emitted Terahertz radiation at room temperature. The microscopic theory is based on a 14 x 14 k • p band-structure calculation in combination with the multi-subband semiconductor Bloch equations. For symmetric GaAs quantum wells grown in (110) direction, an oscillatory dependence of the injection currents on the exciting photon energy is obtained. The results of the microscopic theory are in good agreement with the measurements. }}, author = {{Duc, H. T. and Pochwala, M. and Förstner, Jens and Meier, Torsten and Priyadarshi, S. and Racu, A. M. and Pierz, K. and Siegner, U. and Bieler, M.}}, booktitle = {{Ultrafast Phenomena in Semiconductors and Nanostructure Materials XV}}, editor = {{Tsen, Kong-Thon and Song, Jin-Joo and Betz, Markus and Elezzabi, Abdulhakem Y.}}, keywords = {{tet_topic_qw}}, publisher = {{SPIE}}, title = {{{Injection currents in (110)-oriented GaAs/AlGaAs quantum wells: recent progress in theory and experiment}}}, doi = {{10.1117/12.876972}}, volume = {{7937}}, year = {{2011}}, } @article{4046, abstract = {{We demonstrate by spin quantum beat spectroscopy that in undoped symmetric (110)-oriented GaAs/AlGaAs single quantum wells, even a symmetric spatial envelope wave function gives rise to an asymmetric in-plane electron Land´e g-factor. The anisotropy is neither a direct consequence of the asymmetric in-plane Dresselhaus splitting nor a direct consequence of the asymmetric Zeeman splitting of the hole bands, but rather it is a pure higher-order effect that exists as well for diamond-type lattices. The measurements for various well widths are very well described within 14 × 14 band k·p theory and illustrate that the electron spin is an excellent meter variable for mapping out the internal—otherwise hidden—symmetries in two-dimensional systems. Fourth-order perturbation theory yields an analytical expression for the strength of the g-factor anisotropy, providing a qualitative understanding of the observed effects.}}, author = {{Hübner, J. and Kunz, S. and Oertel, S. and Schuh, D. and Pochwała, M. and Duc, H. T. and Förstner, Jens and Meier, Torsten and Oestreich, M.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, keywords = {{tet_topic_qw}}, number = {{4}}, pages = {{041301(R)}}, publisher = {{American Physical Society (APS)}}, title = {{{Electron g-factor anisotropy in symmetric (110)-oriented GaAs quantum wells}}}, doi = {{10.1103/physrevb.84.041301}}, volume = {{84}}, year = {{2011}}, } @article{43202, abstract = {{For numerous applications, the computation and provision of exact derivative information plays an important role for optimizing the considered system. This paper introduces the technique of algorithmic differentiation, a method to compute derivatives of arbitrary order within working precision. This derivative information will be combined with a calculus-based optimization algorithm to optimize a non-trivially shaped laser pulse which coherently steers the electron dynamics in a semiconductor quantum wire. Numerical results illustrating the cost for the derivative computation and the optimization process are presented and discussed.}}, author = {{Meier, Torsten and Reichelt, Matthias and Walther, A.}}, journal = {{Photonics and Nanostructures - Fundamentals and Applications}}, number = {{4}}, pages = {{328--336}}, publisher = {{Elsevier}}, title = {{{Calculus-based optimization of the electron dynamics in nanostructures}}}, doi = {{10.1016/j.photonics.2011.03.006}}, volume = {{9}}, year = {{2011}}, } @article{52867, author = {{Grimme, Britta and Fuchs, Susanne and Perrier, Pascal and Schöner, Gregor}}, journal = {{Motor control}}, number = {{1}}, pages = {{5–33}}, publisher = {{Human Kinetics, Inc.}}, title = {{{Limb versus speech motor control: A conceptual review}}}, volume = {{15}}, year = {{2011}}, } @book{41965, editor = {{Brinkmann, Annette and Burrichter, Rita and Decker, Claudia}}, publisher = {{LiT Verlag}}, title = {{{Lernprozesse professionell begleiten. Beiträge des Paderborner Grundschultages 2009 zu Diagnose und Förderung}}}, volume = {{16}}, year = {{2011}}, } @inbook{65340, author = {{Droß-Krüpe, Kerstin}}, booktitle = {{Wearing the Cloak. Dressing the Soldier in Roman Times}}, editor = {{Nosch, M.-L.}}, pages = {{13--18}}, title = {{{Purchase Orders of Military Garments from Papyri of Roman Egypt}}}, volume = {{10}}, year = {{2011}}, } @book{65107, author = {{Droß-Krüpe, Kerstin}}, pages = {{304}}, publisher = {{Harrassowitz}}, title = {{{Wolle – Weber – Wirtschaft. Die Textilproduktion der römischen Kaiserzeit im Spiegel der papyrologischen Überlieferung}}}, year = {{2011}}, }