@article{43264, abstract = {{On the basis of a microscopic theory, the signatures of many-particle correlations in Two-Dimensional Fourier-Transform Spectra (2D-FTS) of semiconductor nanostructures are identified and compared to experimental data. Spectra in the photon energy range of the heavy-hole and light-hole excitonic resonances show characteristic features due to correlations, which depend on the relative polarization directions of the excitation pulses.}}, author = {{Kuznetsova, I. and Thomas, P. and Meier, Torsten and Zhang, T. and Li, X. and Mirin, R.P. and Cundiff , S. T.}}, journal = {{Solid state communications}}, number = {{3}}, pages = {{154--158}}, publisher = {{Pergamon}}, title = {{{Signatures of Many-Particle Correlations in Two-Dimensional Fourier-Transform Spectra of Semiconductor Nanostructures}}}, doi = {{10.1016/j.ssc.2007.02.010}}, volume = {{142}}, year = {{2007}}, } @inproceedings{44113, abstract = {{Optical two dimensional Fourier transform spectra of excitonic resonances in semiconductors are measured and calculated. They provide insight into many-body interactions in direct gap semiconductors by separating the contributions to the coherent optical nonlinear response.}}, author = {{Meier, Torsten and Cundiff, S.T. and Zhang, T. and Li, X. and Bristow, A. D. and Kuznetsova, I. and Thomas, P. and Yang, L. and Schweigert, I. V. and Mukamel, S. and Mirin, R. P.}}, booktitle = {{Laser Science XXIII Organic Materials and Devices for Displays and Energy Conversion}}, isbn = {{1-55752-846-2}}, location = {{San Jose, California United States}}, title = {{{Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors}}}, doi = {{10.1364/LS.2007.LWJ3}}, year = {{2007}}, } @article{23488, abstract = {{Studies of current dynamics in solids have been hindered by insufficiently brief trigger signals and electronic detection speeds. By combining a coherent control scheme with photoelectron spectroscopy, we generated and detected lateral electron currents at a metal surface on a femtosecond time scale with a contact-free experimental setup. We used coherent optical excitation at the light frequencies ωa and ωa/2 to induce the current, whose direction was controlled by the relative phase between the phase-locked laser excitation pulses. Time- and angle-resolved photoelectron spectroscopy afforded a direct image of the momentum distribution of the excited electrons as a function of time. For the first (n = 1) image-potential state of Cu(100), we found a decay time of 10 femtoseconds, attributable to electron scattering with steps and surface defects.}}, author = {{Gudde, J. and Rohleder, M. and Meier, Torsten and Koch, S. W. and Hofer, U.}}, issn = {{0036-8075}}, journal = {{Science}}, number = {{5854}}, pages = {{1287--1291}}, title = {{{Time-Resolved Investigation of Coherently Controlled Electric Currents at a Metal Surface}}}, doi = {{10.1126/science.1146764}}, volume = {{318}}, year = {{2007}}, } @article{23487, abstract = {{Optical 2D Fourier transform spectroscopy (2DFTS) provides insight into the many-body interactions in direct gap semiconductors by separating the contributions to the coherent nonlinear optical response. We demonstrate these features of optical 2DFTS by studying the heavy-hole and light-hole excitonic resonances in a gallium arsenide quantum well at low temperature. Varying the polarization of the incident beams exploits selection rules to achieve further separation. Calculations using a full many-body theory agree well with experimental results and unambiguously demonstrate the dominance of many-body physics.}}, author = {{Zhang, T. and Kuznetsova, I. and Meier, Torsten and Li, X. and Mirin, R. P. and Thomas, P. and Cundiff, S. T.}}, issn = {{0027-8424}}, journal = {{Proceedings of the National Academy of Sciences (PNAS)}}, number = {{36}}, pages = {{14227--14232}}, title = {{{Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors}}}, doi = {{10.1073/pnas.0701273104}}, volume = {{104}}, year = {{2007}}, } @inproceedings{44115, abstract = {{The coherent optical injection and temporal decay of spin and charge currents in semiconductor heterostructures has be described on a microscopic basis including Coulomb and phononic effects up to the level of second-order Born contributions. In this talk the previously used two-band effective mass approach is extended to a multi-band approach using realistic microscopic kp matrix elements. Furthermore, the influence of heavy-hole light-hole band-mixing contained in the kp calculation and its effects on the microscopic semiconductor dynamics is demonstrated and discussed.}}, author = {{Meier, Torsten and Pasenow, B. and Koch, S.W. and Duc, Huynh Thanh}}, booktitle = {{71. Annual meeting 2007 and DPG-spring meeting of the division condensed matte}}, location = {{Regensburg, Germany}}, title = {{{Aspects of heavy-hole light-hole band mixing effects on the coherent optical generation of charge and spin currents in semiconductor heterostructures}}}, volume = {{42}}, year = {{2007}}, } @article{13683, author = {{Stekolnikov, A. A. and Seino, K. and Bechstedt, F. and Wippermann, S. and Schmidt, Wolf Gero and Calzolari, A. and Nardelli, M. Buongiorno}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{2}}, title = {{{Hexagon versus Trimer Formation in In Nanowires on Si(111): Energetics and Quantum Conductance}}}, doi = {{10.1103/physrevlett.98.026105}}, volume = {{98}}, year = {{2007}}, } @article{13678, author = {{Blankenburg, S. and Schmidt, Wolf Gero}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{19}}, title = {{{Long-Range Chiral Recognition due to Substrate Locking and Substrate-Adsorbate Charge Transfer}}}, doi = {{10.1103/physrevlett.99.196107}}, volume = {{99}}, year = {{2007}}, } @article{13681, author = {{Wippermann, S. and Schmidt, Wolf Gero and Calzolari, A. and Nardelli, M. Buongiorno and Stekolnikov, A.A. and Seino, K. and Bechstedt, F.}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{4045--4047}}, title = {{{Quantum conductance of In nanowires on Si(111) from first principles calculations}}}, doi = {{10.1016/j.susc.2007.04.053}}, year = {{2007}}, } @article{13682, author = {{Bernholc, J. and Lu, W. and Nakhmanson, S. M. and Hahn, P.H. and Meunier, V. and Buongiorno Nardelli, M. and Schmidt, Wolf Gero}}, issn = {{0026-8976}}, journal = {{Molecular Physics}}, pages = {{147--156}}, title = {{{Atomic scale design of nanostructures}}}, doi = {{10.1080/00268970701189186}}, year = {{2007}}, } @article{13680, author = {{Blankenburg, S and Schmidt, Wolf Gero}}, issn = {{0957-4484}}, journal = {{Nanotechnology}}, title = {{{Steric effects and chirality in the adsorption of glycine and phenylglycine on Cu(110)}}}, doi = {{10.1088/0957-4484/18/42/424030}}, volume = {{18}}, year = {{2007}}, } @article{13677, author = {{Thierfelder, C. and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{19}}, title = {{{Ethanol adsorbed on ice: A first-principles study}}}, doi = {{10.1103/physrevb.76.195426}}, volume = {{76}}, year = {{2007}}, } @inbook{43269, abstract = {{The derivation of a microscopic many-body theory for the nonlinear optical response of semiconductors is reviewed. At the Hartree–Fock level, the semiconductor Bloch equations include many-body effects via band gap and field renormalization. These equations are sufficient to describe excitonic resonances as they appear already in the linear absorption spectra. An adequate description of nonlinear optical effects in semiconductors beyond the Hartree–Fock level includes Coulomb interaction induced carrier correlations. Different schemes have been developed to treat such correlation effects. As two examples, the second-order Born approximation and the dynamics-controlled truncation scheme are introduced and analyzed. In addition to the derivation of the equations of motion, a few examples are presented which highlight important signatures of many-body correlations in the optical response of semiconductors.}}, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Quantum Coherence: From Quarks to Solids}}, isbn = {{978-3-540-30085-4}}, pages = {{115--152}}, publisher = {{Springer, Berlin, Heidelberg}}, title = {{{Microscopic Theory of Coherent Semiconductor Optics}}}, doi = {{10.1007/11398448_4}}, volume = {{689}}, year = {{2006}}, } @article{23493, abstract = {{A microscopic analysis is presented for the extreme nonlinear optical response of semiconductor quantum wells and wires after intense excitation with femtosecond laser pulses. In this regime, the light–matter interaction is the dominant eneregy scale, leading to a number of interesting effects such as carrier-wave Rabi flopping, Mollow splitting, and the creation of higher harmonics. The results presented here were obtained by evaluating the semiconductor Bloch equations without the rotating wave approximation. The electronic dispersion of semiconductor nanostructures is shown to have a characteristic influence on the extreme nonlinear optical response, whereas the relative importance of the carrier Coulomb interaction decreases with increasing excitation intensities.}}, author = {{Golde, Daniel and Meier, Torsten and Koch, Stephan W.}}, issn = {{0740-3224}}, journal = {{Journal of the Optical Society of America B}}, number = {{12}}, pages = {{2559--2565}}, title = {{{Microscopic analysis of extreme nonlinear optics in semiconductor nanostructures}}}, doi = {{10.1364/josab.23.002559}}, volume = {{23}}, year = {{2006}}, } @article{23495, abstract = {{The method of angular photonic correlations of spontaneous emission is introduced as an experimental, purely optical scheme to characterize disorder in semiconductor nanostructures. The theoretical expression for the angular correlations is derived and numerically evaluated for a model system. The results demonstrate how the proposed experimental method yields direct information about the spatial distribution of the relevant states and thus on the disorder present in the system.}}, author = {{Bozsoki, P. and Thomas, P. and Kira, M. and Hoyer, W. and Meier, Torsten and Koch, S. W. and Maschke, K. and Varga, I. and Stolz, H.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{22}}, title = {{{Characterization of Disorder in Semiconductors via Single-Photon Interferometry}}}, doi = {{10.1103/physrevlett.97.227402}}, volume = {{97}}, year = {{2006}}, } @inproceedings{43265, abstract = {{The dynamics of charge and spin currents generated by two-color femtosecond laser pulses is investigated. Non-Markovian memory effects lead to oscillations in the coherent transients. Consequences arising from the heavy-hole light-hole coupling are predicted.}}, author = {{Meier, Torsten and Vu, Q.T. and Duc, H.T. and Pasenow, B. and Haug, H. and Koch, S.W.}}, booktitle = {{International Conference on Ultrafast Phenomena XV}}, isbn = {{1-55752-810-1}}, location = {{Pacific Grove, California United States}}, publisher = {{Optical Society of America}}, title = {{{Microscopic Many-Body Analysis of Ultrafast Photocurrents in Semiconductor Nanostructures}}}, doi = {{10.1364/UP.2006.TuD8}}, volume = {{88}}, year = {{2006}}, } @article{23491, abstract = {{A brief overview of a consistent microscopic approach to model the optical and electronic properties of semiconductor nanostructures is presented. Coupled semiconductor Bloch and Maxwell equations are used to investigate the performance of semiconductor microcavity structures, photonic band gap systems, and lasers. The predictive potential of the microscopic theory is demonstrated for several examples of practical importance. Optical gain and output characteristics are computed for modern vertical external cavity surface emitting laser structures. It is shown how design flexibilities can be used to optimize the device performance. Nanostructures are proposed where semiconductor quantum wells are embedded in one-dimensional photonic crystals. For field modes spectrally below the photonic band edge it is shown that the optical gain and absorption can be enhanced by more than one order of magnitude over the value of the homogeneous medium. The increased gain can be used for laser action by placing quantum wells and a suitably designed photonic crystal structure inside a microcavity.}}, author = {{Thränhardt, A. and Meier, Torsten and Reichelt, Matthias and Schlichenmaier, C. and Pasenow, B. and Kuznetsova, I. and Becker, S. and Stroucken, T. and Hader, J. and Zakharian, A.R. and Moloney, J.V. and Chow, W.W. and Koch, S.W.}}, issn = {{0022-3093}}, journal = {{Journal of Non-Crystalline Solids}}, number = {{23-25}}, pages = {{2480--2483}}, title = {{{Microscopic modeling of the optical properties of semiconductor nanostructures}}}, doi = {{10.1016/j.jnoncrysol.2006.02.064}}, volume = {{352}}, year = {{2006}}, } @article{23492, abstract = {{The coherent ultrafast optical injection and the temporal evolution of charge and spin currents in semiconductors is analyzed using a microscopic many-body theory. The approach is based on the semiconductor Bloch equations and includes light-field-induced intraband and interband excitations, excitonic effects, and carrier–LO-phonon and carrier-carrier scattering processes. The relaxation effects are treated both in the second Born-Markov approximation and on the level of quantum kinetic theory including memory effects. The dynamics of the charge and spin currents is evaluated numerically for a one-dimensional model system. The dependence of the currents and their decay on the temperature, the excitation intensities, and the frequencies of the incident light fields is discussed. Whereas the overall decay dynamics is described well within the Markov approximation, the quantum kinetic theory predicts additional oscillatory signatures in the current transients.}}, author = {{Duc, H. T. and Vu, Q. T. and Meier, Torsten and Haug, H. and Koch, S. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{16}}, title = {{{Temporal decay of coherently optically injected charge and spin currents due to carrier–LO-phonon and carrier-carrier scattering}}}, doi = {{10.1103/physrevb.74.165328}}, volume = {{74}}, year = {{2006}}, } @inbook{44120, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Photonic Crystals: Advances in Design, Fabrication, and Characterization}}, editor = {{Busch, Kurt and Lölkes, Stefan and Wehrspohn, Ralf B. and Föll, Helmut}}, pages = {{43--62}}, publisher = {{John Wiley & Sons}}, title = {{{Semiconductor Optics in Photonic Crystal Structures}}}, year = {{2006}}, } @inbook{43270, abstract = {{The linear and nonlinear optical properties of semiconductors are strongly influenced by the Coulomb interaction among the photoexcited carriers. Within the framework of the semiconductor Bloch equations such many-body effects can be described on the basis of a microscopic theory. In this article, we briefly review our recent contributions to two specific topics. First, the coherent optical generation of charge and spin currents and their subsequent decay via scattering processes is discussed. As a second example, the spatially-inhomogeneous optical properties of hybrid structures which consist of photonic crystals and semiconductor nanostructures are described. Many of the numerical results have been obtained using massively parallel computer programs which were run on the IBM p690-Cluster Jump in Jülich.}}, author = {{Meier, Torsten and Duc, Huynh Thanh and Reichelt, Matthias and Pasenow, B. and Stroucken, T. and Koch, S.W.}}, booktitle = {{Germany in NIC Series Vol. 32}}, editor = {{Munster, G. and Wolf, D. and Kremer, M.}}, isbn = {{3-00-017351-X}}, pages = {{219--226}}, publisher = {{John von Neumann Institute for Computing}}, title = {{{Computational Optoelectronics of Semiconductor Nanostructures including Many-Body Effects}}}, year = {{2006}}, } @inproceedings{44294, abstract = {{The band alignment of GaNAs in heterostructures is determined by investigating the energetically lowest optical band-to-band transition of In0.23Ga0.77As/GaNyAs1−y samples with varying y. In a type II alignment this transition is between states located in different layers. Photoreflectance, photoluminescence, and the radiative decay of excited carrier densities are both measured and microscopically modeled. The bandstructure for every sample is computed. Based on this bandstructure all optical properties and the radiative decay are computed using the semiconductor Bloch [1] and luminescence [2] equations including electron-electron and electron-phonon interaction on scattering level. Thus the modeling is consistent and without free parameters. Overall good agreement between theory and experiment is achieved and used to explain all experimental features and to determine the band alignment}}, author = {{Meier, Torsten and Schlichenmaier, C. and Thraenhardt, Angela and Koch, S.W. and Hantke, Kristian and Ruehle, Wolfgang and Gruening, Heiko and Klar, Peter J. and Heimbrodt, Wolfgang and Hader, J. and Moloney, Jerome V.}}, booktitle = {{Meeting of the German Physical Society, Solid-State Physics Section, and the European Physical Society Condensed Matter Division}}, location = {{ Dresden, Germany}}, title = {{{Type I type II transition in optical spectra-experiments and microscopic theory}}}, volume = {{41}}, year = {{2006}}, }