@inproceedings{43263, abstract = {{Employing the quantum interference among one- and two-photon excitations induced by ultrashort two-color laser pulses it is possible to generate charge and spin currents in semiconductors and semiconductor nanostructures on femtosecond time scales. Here, it is reviewed how the excitation process and the dynamics of such photocurrents can be described on the basis of a microscopic many-body theory. Numerical solutions of the semiconductor Bloch equations (SBE) provide a detailed description of the time-dependent material excitations. Applied to the case of photocurrents, numerical solutions of the SBE for a two-band model including many-body correlations on the second-Born Markov level predict an enhanced damping of the spin current relative to that of the charge current. Interesting effects are obtained when the scattering processes are computed beyond the Markovian limit. Whereas the overall decay of the currents is basically correctly described already within the Markov approximation, quantum-kinetic calculations show that memory effects may lead to additional oscillatory signatures in the current transients. When transitions to coupled heavy- and light-hole valence bands are incorporated into the SBE, additional charge and spin currents, which are not described by the two-band model, appear.}}, author = {{Meier, Torsten and Pasenow, B. and Duc, H.T. and Vu, Q.T. and Haug, H. and Koch, S.W.}}, booktitle = {{Ultrafast Phenomena in Semiconductors and Nanostructure Materials XI and Semiconductor Photodetectors IV}}, publisher = {{SPIE}}, title = {{{Ultrafast dynamics of photoexcited charge and spin currents in semiconductor nanostructures}}}, doi = {{10.1117/12.696338}}, volume = {{6471}}, year = {{2007}}, } @inproceedings{44117, abstract = {{Two-Dimensional Fourier-Transform-Spectroscopy (2DFTS) is a novel method for the experimental investigation of many-body interactions in semiconductor nanostructures [1]. It displays directly the heavy-hole (hh) and light-hole (lh) excitonic transitions in III-V-quantum wells along the main diagonal of a two-dimensional plot which is spanned by the excitation energy −ħωτ and the emission energy ħωτ. In addition, characteristic signatures due to continuum excitations appear as well as mixed peaks in off-diagonal positions resulting from various couplings. Using a one-dimensional tight-binding model which contains the correct selection rules we compute 2DFTS in the coherent χ(3)-limit. By comparing theoretical spectra resulting from different orders in the Coulomb interaction we can clearly identify the influence of the many-particle interaction on the various signatures that are visible in the spectrograms. The distribution of the peak heights, their magnitude, and their lineshape are of particular interest. Co-circularly polarized excitation pulses are considered.}}, author = {{Meier, Torsten and Kuznetsova, Irina and Thomas, Peter and Zhang, Tianhao and Cundiff, Steven T.}}, booktitle = {{International Quantum Electronics Conference}}, isbn = {{1-4244-931-4}}, location = {{Munich, Germany}}, title = {{{Investigation of Coulomb-induced coupling in semiconductor nanostructures using 2D Fourier-Transform-Spectroscopy}}}, year = {{2007}}, } @inproceedings{44118, abstract = {{Many-body correlations of excitons in semiconductors are explored experimentally with two-dimensional Fourier transform spectroscopy and modeled by a microscopic coherent χ(3) theory beyond the Hartree-Fock approximation with qualitative agreements under different excitation conditions.}}, author = {{Meier, Torsten and Zhang, Tianhao and Li, Xiaoqin and Cundiff, S.T. and Mirin, R. P. and Kuznetsova, Irina and Thomas, P.}}, booktitle = {{Quantum Electronics and Laser Science Conference}}, isbn = {{1557528349}}, location = {{Baltimore, Maryland United States}}, publisher = {{Optical Society of America}}, title = {{{Experimental and theoretical studies of exciton correlations using optical two-dimensional fourier transform spectroscopy}}}, year = {{2007}}, } @article{44114, 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 = {{Meier, Torsten and Zhang, Tianhao and Kuznetsova, Irina and Li, Xiaoqin and Mirin, R. P. and Thomas, Peter and Cundiff, S.T.}}, journal = {{Proceedings of the National Academy of Sciences}}, number = {{36}}, pages = {{14227--14232}}, title = {{{Multidimensional ultrafast spectroscopy special feature: polarization-dependent optical 2d fourier transform spectroscopy of semiconductors}}}, doi = {{10.1073/pnas.0701273104}}, volume = {{104}}, year = {{2007}}, } @book{23486, author = {{Meier, Torsten and Thomas, Peter and Koch, Stephan W.}}, isbn = {{9783540325543}}, title = {{{Coherent Semiconductor Optics}}}, doi = {{10.1007/978-3-540-32555-0}}, volume = {{1}}, year = {{2007}}, } @article{43262, abstract = {{A microscopic theory for the luminescence of ordered semiconductors is modified to describe photoluminescence of strongly disordered semiconductors. The approach includes both diagonal disorder and the many-body Coulomb interaction. As a case study, the light emission of a correlated plasma is investigated numerically for a one-dimensional two-band tight-binding model. The band structure of the underlying ordered system is assumed to correspond to either a direct or an indirect semiconductor. In particular, luminescence and absorption spectra are computed for various levels of disorder and sample temperature to determine thermodynamic relations, the Stokes shift, and the radiative lifetime distribution.}}, author = {{Bozsoki, P. and Kira, M. and Hoyer, W. and Meier, Torsten and Varga, I. and Thomas, P. and Koch, S.W.}}, journal = {{Journal of Luminescence}}, number = {{1}}, pages = {{99--112}}, publisher = {{North-Holland}}, title = {{{Microscopic modeling of photoluminescence of strongly disordered semiconductors}}}, doi = {{10.1016/j.jlumin.2006.02.005}}, volume = {{124}}, year = {{2007}}, } @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}}, } @article{1749, author = {{Nau, D. and Bertram, R.P. and Buse, K. and Zentgraf, Thomas and Kuhl, J. and Tikhodeev, S.G. and Gippius, N.A. and Giessen, H.}}, issn = {{0946-2171}}, journal = {{Applied Physics B}}, number = {{4}}, pages = {{543--547}}, publisher = {{Springer Nature}}, title = {{{Optical switching in metallic photonic crystal slabs with photoaddressable polymers}}}, doi = {{10.1007/s00340-005-2103-z}}, volume = {{82}}, year = {{2006}}, } @article{1750, author = {{Zentgraf, Thomas and Christ, A. and Kuhl, J. and Gippius, N. A. and Tikhodeev, S. G. and Nau, D. and Giessen, H.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{11}}, publisher = {{American Physical Society (APS)}}, title = {{{Metallodielectric photonic crystal superlattices: Influence of periodic defects on transmission properties}}}, doi = {{10.1103/physrevb.73.115103}}, volume = {{73}}, year = {{2006}}, } @article{1751, author = {{Rockstuhl, C. and Zentgraf, Thomas and Guo, H. and Liu, N. and Etrich, C. and Loa, I. and Syassen, K. and Kuhl, J. and Lederer, F. and Giessen, H.}}, issn = {{0946-2171}}, journal = {{Applied Physics B}}, number = {{1-2}}, pages = {{219--227}}, publisher = {{Springer Nature}}, title = {{{Resonances of split-ring resonator metamaterials in the near infrared}}}, doi = {{10.1007/s00340-006-2205-2}}, volume = {{84}}, year = {{2006}}, }