@article{13730, abstract = {{ The influence of hydrogen on the reconstruction of InP(001) surfaces is studied by first-principles calculations. One-monolayer phosphorus forming oppositely buckled dimers with one hydrogen adsorbed per dimer is energetically favored for a wide range of surface preparation conditions. The electronic structure and STM image calculated for this adsorbate geometry agree well with the experimental findings obtained after annealing of MOVPE-grown InP samples. The Si(001)-like surface ordering as well as the surface band gap of more than 1 eV, supposedly arising from electron correlation effects [Li et al., Phys. Rev. Lett.82, 1879 (1999)], are naturally explained by the hydrogen-stabilized surface structure favored by the total-energy calculations. }}, author = {{Hahn, P. H. and Schmidt, Wolf Gero}}, issn = {{0218-625X}}, journal = {{Surface Review and Letters}}, number = {{2-3}}, pages = {{163--167}}, title = {{{Surface Ordering of P-rich InP(001): Hydrogen Stabilization vs Electron Correlation}}}, doi = {{10.1142/s0218625x03004913}}, volume = {{10}}, year = {{2003}}, } @article{13728, author = {{Hahn, P. H. and Schmidt, Wolf Gero and Bechstedt, F. and Pulci, O. and Del Sole, R.}}, issn = {{0163-1829}}, journal = {{Physical Review B}}, pages = {{033311}}, title = {{{P-richGaP(001)(2×1)/(2×2)surface:  A hydrogen-adsorbate structure determined from first-principles calculations}}}, doi = {{10.1103/physrevb.68.033311}}, volume = {{68}}, year = {{2003}}, } @article{13733, author = {{Schmidt, Wolf Gero and Hahn, P. H. and Bechstedt, F. and Esser, N. and Vogt, P. and Wange, A. and Richter, W.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{12}}, pages = {{126101}}, title = {{{InP(001)-(2×1) Surface: A Hydrogen Stabilized Structure}}}, doi = {{10.1103/physrevlett.90.126101}}, volume = {{90}}, year = {{2003}}, } @article{13726, author = {{Castillo, C. and Mendoza, Bernardo S. and Schmidt, Wolf Gero and Hahn, P. H. and Bechstedt, F.}}, issn = {{0163-1829}}, journal = {{Physical Review B}}, pages = {{041310(R)}}, title = {{{Layer-by-layer analysis of surface reflectance anisotropy in semiconductors}}}, doi = {{10.1103/physrevb.68.041310}}, volume = {{68}}, year = {{2003}}, } @article{13727, author = {{Wang, Shuchun and Lu, Wenchang and Schmidt, Wolf Gero and Bernholc, J.}}, issn = {{0163-1829}}, journal = {{Physical Review B}}, pages = {{035329}}, title = {{{Nanowire-induced optical anisotropy of the Si(111)-In surface}}}, doi = {{10.1103/physrevb.68.035329}}, volume = {{68}}, year = {{2003}}, } @article{13732, author = {{Seino, K. and Schmidt, Wolf Gero and Preuss, M. and Bechstedt, F.}}, issn = {{1520-6106}}, journal = {{The Journal of Physical Chemistry B}}, pages = {{5031--5035}}, title = {{{Uracil Adsorbed on Si(001):  Structure and Energetics}}}, doi = {{10.1021/jp0342531}}, volume = {{107}}, year = {{2003}}, } @article{13725, author = {{Lu, Wenchang and Schmidt, Wolf Gero and Bernholc, J.}}, issn = {{0163-1829}}, journal = {{Physical Review B}}, pages = {{115327}}, title = {{{Cycloaddition reaction versus dimer cleavage at theSi(001):C5H8interface}}}, doi = {{10.1103/physrevb.68.115327}}, volume = {{68}}, year = {{2003}}, } @article{13731, author = {{Seino, K. and Schmidt, Wolf Gero and Furthmüller, J. and Bechstedt, F.}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{988--992}}, title = {{{Chemisorption of pyrrole (C4H4NH) on Si(001) calculated from first-principles}}}, doi = {{10.1016/s0039-6028(03)00159-6}}, volume = {{532-535}}, year = {{2003}}, } @article{13723, author = {{Bechstedt, F. and Del Sole, R. and Glutsch, S. and Hahn, P. H. and Pulci, O. and Schmidt, Wolf Gero}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, number = {{3}}, pages = {{469--479}}, title = {{{Many-body and overlayer effects on surface optical properties}}}, doi = {{10.1002/pssb.200303827}}, volume = {{240}}, year = {{2003}}, } @article{13724, author = {{Pristovsek, M. and Tsukamoto, S. and Ohtake, A. and Koguchi, N. and Orr, B. G. and Schmidt, Wolf Gero and Bernholc, J.}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{91--98}}, title = {{{Gallium-rich reconstructions on GaAs(001)}}}, doi = {{10.1002/pssb.200301885}}, volume = {{240}}, year = {{2003}}, } @article{4310, abstract = {{Nonlinear propagation of optical pulses through an extended bulk semiconductor is investigated using the coupled semiconductor Maxwell‐Bloch equations including excitation induced correlations. For short pulse excitation around the exciton resonance, the theory describes the development of polariton beats and their suppression at increasing input pulse intensities due to the coupling of single exciton states to the Coulomb‐correlated continuum of two‐exciton states. A comparison of the theoretical results with experimental observations for CdSe bulk material is presented.}}, author = {{Förstner, Jens and Knorr, A. and Kuckenburg, S. and Meier, Torsten and Koch, S.W. and Giessen, H. and Linden, S. and Kuhl, J.}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, keywords = {{tet_topic_polariton}}, number = {{1}}, pages = {{453--457}}, publisher = {{Wiley}}, title = {{{Nonlinear Polariton Pulse Propagation in Bulk Semiconductors}}}, doi = {{10.1002/1521-3951(200009)221:1<453::aid-pssb453>3.0.co;2-q}}, volume = {{221}}, year = {{2002}}, } @article{43294, abstract = {{The quantum dynamics of an ensemble of interacting electrons in an array of random scatterers is treated using a numerical approach for the calculation of average values of quantum operators and time correlation functions in the Wigner representation. The Fourier transform of the product of matrix elements of the dynamic propagators obeys an integral Wigner-Liouville-type equation. Initial conditions for this equation are given by the Fourier transform of the Wiener path-integral representation of the matrix elements of the propagators at the chosen initial times. This approach combines both molecular dynamics and Monte Carlo methods and computes numerical traces and spectra of the relevant dynamical quantities such as momentum-momentum correlation functions and spatial dispersions. Considering, as an application, a system with fixed scatterers, the results clearly demonstrate that the many-particle interaction between the electrons leads to an enhancement of the conductivity and spatial dispersion compared to the noninteracting case.}}, author = {{Meier, Torsten and Filinov, V. and Thomas, P. and Varga, I. and Bonitz, M. and Fortov, V. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{16}}, publisher = {{American Physical Society}}, title = {{{Interacting electrons in a one-dimensional random array of scatterers: A quantum dynamics and Monte Carlo study}}}, doi = {{10.1103/PhysRevB.65.165124}}, volume = {{65}}, year = {{2002}}, } @article{43295, abstract = {{The influence of coherent photoexcited excitons on the absorption spectra and the Four Wave Mixing response of ZnSe/ZnMgSSe quantum wells is investigated for various polarization configurations. For purely resonant excitation at the heavy-hole-exciton a blue shift and an increasing homogeneous line width of the exciton absorption peak is found. The clear and stable blue shift shows a linear dependence on excitation fluence both in experiment and theory with different slopes for the different pump and probe polarization configurations. The equivalence of pump and probe, and Four Wave Mixing results is shown experimentally.}}, author = {{Meier, Torsten and Wachter, S. and Maute, M. and Kalt, H. and Galbraith, I. and Sieh, C. and Koch, S.W.}}, journal = {{Physica B: Condensed Matter}}, number = {{1-4}}, pages = {{309--313}}, publisher = {{North-Holland}}, title = {{{Excitation induced shift and broadening of the exciton resonance}}}, doi = {{10.1016/S0921-4526(01)01400-4}}, volume = {{314}}, year = {{2002}}, } @article{43292, abstract = {{Physicists have realized during the last two decades that the physical properties of many condensed-matter systems are often best described in terms of lumps of charge, known as quasiparticles, rather than by electrons and ions. In a crystal under equlibrium conditions, for example, the mutual repulsion of the electrons leads to a cloud of positive charge surrounding each individual electron. This "dressing" of electrons leads to charge screening. In other words, a test charge placed far from an electron will feel the influence of a new entity with a smaller charge, rather than the charge on the "bare" electron.}}, author = {{Meier, Torsten and Koch, S.W.}}, journal = {{Physics World}}, number = {{2}}, pages = {{24--25}}, publisher = {{IOP Publishing}}, title = {{{Particles get all dressed up}}}, doi = {{10.1088/2058-7058/15/2/36}}, volume = {{15}}, year = {{2002}}, } @article{43291, abstract = {{On the basis of a tight-binding model for a strongly disordered semiconductor with correlated conduction- and valence-band disorder a coherent dynamical intraband effect is analyzed. For systems that are excited by two specially designed ultrashort light-pulse sequences delayed by τ relatively to each other echolike phenomena are predicted to occur. In addition to the interband photon echo which shows up at exactly t=2τ relative to the first pulse, the system responds with two spontaneous intraband current pulses preceding and following the appearance of the photon echo. The temporal splitting depends on the electron-hole mass ratio. Calculating the population relaxation rate due to Coulomb scattering, it is concluded that the predicted new dynamical effect should be experimentally observable in an interacting and strongly disordered system, such as the Quantum Coulomb Glass.}}, author = {{Meier, Torsten and Schlichenmaier, C. and Varga, I. and Thomas, P. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{8}}, publisher = {{American Physical Society}}, title = {{{Optically induced coherent intraband dynamics in disordered semiconductors}}}, doi = {{10.1103/PhysRevB.65.085306}}, volume = {{65}}, year = {{2002}}, } @inproceedings{44127, abstract = {{A microscopic theory for optical semiconductor nonlinearities systematically including Coulomb correlation effects is able to explain AC Stark shifts measured with all possible pump/probe circular polarizations and gives evidence for a 3-level-atom-like intervalence band coherence.}}, author = {{Meier, Torsten and Gibbs, H.M. and Khitrova, G. and Ell, C. and Binder, R. and Hoyer, W. and Kira, M. and Koch, S.W. and Sieh, C.}}, booktitle = {{Nonlinear Optics: Materials, Fundamentals and Applications}}, isbn = {{1-55752-721-0}}, location = {{Wailea, Maui, Hawaii United States}}, publisher = {{Optical Society of America}}, title = {{{Higher-Order Correlations and Semiconductor Optical Nonlinearities}}}, doi = {{10.1364/NLO.2002.WA1}}, year = {{2002}}, } @article{43293, abstract = {{We present a derivation of Förster coupling between two quantum dots by solving the equation of motion for the material excitation simultaneously with Maxwells equations. This allows us to identify the Förster process with the short-range contribution of the coupling that is mediated by the total electric field. The dependence of the coupling on the distance R of the dots is ∝ R—3, i.e. the rates follow the well-known R—6 behaviour. For distances between the sites longer than a quarter of the wavelength of light there is a cross-over to coupling due to the retarded light field, which is ∝ R—1, i.e. the rates are ∝ R—2.}}, author = {{Meier, Torsten and Thomas, P. and Möller, M. and Eichmann, R. and Stroucken, T. and Knorr, A.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{25--29}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Microscopic Foundation of the Förster Excitonic Energy Transfer Process}}}, doi = {{10.1002/1521-3951(200203)230:1<25::AID-PSSB25>3.0.CO;2-8}}, volume = {{230}}, year = {{2002}}, } @article{43297, abstract = {{A microscopic many-body theory describing the optical and electronic properties of semiconductors and semiconductor nanostructures is briefly reviewed. At the semiclassical level, the optical response is computed using Maxwell's equations together with the semiconductor Bloch equations which describe the dynamics of the diagonal and the off-diagonal terms of the reduced single-particle density matrix. These equations include the coupling between the semiconductor and the optical field as well as Coulomb many-body interactions among the optically excited carriers. Under quasi-equilibrium conditions, luminescence spectra can be obtained from absorption spectra on the basis of the Kubo–Martin–Schwinger relation for conditions usually limited to the regime of optical gain (lasers). More generally, light emission has to be computed at a fully quantum mechanical level leading to semiconductor luminescence equations.}}, author = {{Meier, Torsten and Koch, S.W. and Hoyer, W. and Kira, M.}}, journal = {{Physica E: Low-Dimensional Systems and Nanostructures}}, number = {{1-2}}, pages = {{45--52}}, publisher = {{North-Holland}}, title = {{{Theory of the optical properties of semiconductor nanostructures}}}, doi = {{10.1016/S1386-9477(02)00358-2}}, volume = {{14}}, year = {{2002}}, } @article{43296, abstract = {{A three-beam configuration is used to investigate the spectrally resolved wave-mixing signal of a ZnSe single quantum well. The spectrum recorded in direction 2 k2–k1 shows coherent oscillations induced by a delayed third pulse with direction k3. Intensity and polarization-dependent measurements indicate that the signal is generated by a combination of four- and six-wave mixing. The origin of the oscillations can be explained qualitatively by a two-level model. The polarization-dependent experimental results require the treatment of many-body correlations and are well explained by microscopic calculations including four-particle correlations up to fifth order in the fields.}}, author = {{Meier, Torsten and Wagner, H.P. and Tranitz, H.-P. and Reichelt, Matthias and Koch, S.W.}}, journal = {{physica status solidi (a)}}, number = {{3}}, pages = {{843--847}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Coherent Oscillations in Multiwave Mixing Due to Higher‐Order Coulomb Correlations}}}, doi = {{10.1002/1521-396X(200204)190:3<843::AID-PSSA843>3.0.CO;2-B}}, volume = {{190}}, year = {{2002}}, } @article{43300, abstract = {{The influence of coupling, correlation, and disorder on exciton and biexciton signatures is investigated using coherent excitation spectroscopy. Different biexciton-induced transitions of a single biexciton state are spectrally resolved. One of the transitions is found to be particularly sensitive to disorder. Mixed biexciton resonances, resulting from attractively interacting heavy and light hole exciton states, are identified. The observations are analyzed on the basis of microscopic model calculations.}}, author = {{Meier, Torsten and Finger, E. and Kraft, S.P. and Hofmann, M. and Koch, S.W. and Stolz, W. and Rühle, W.W.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{424--434}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Coulomb correlations and biexciton signatures in coherent excitation spectroscopy of semiconductor quantum wells}}}, doi = {{10.1002/1521-3951(200211)234:1<424::AID-PSSB424>3.0.CO;2-V}}, volume = {{234}}, year = {{2002}}, }