@article{13666, author = {{Wippermann, S. and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{23}}, title = {{{Water adsorption on clean Ni(111) and p(2×2)-Ni(111)-O surfaces calculated from first principles}}}, doi = {{10.1103/physrevb.78.235439}}, volume = {{78}}, year = {{2008}}, } @article{13671, author = {{Hermann, A. and Schmidt, Wolf Gero and Schwerdtfeger, P.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{20}}, title = {{{Resolving the Optical Spectrum of Water: Coordination and Electrostatic Effects}}}, doi = {{10.1103/physrevlett.100.207403}}, volume = {{100}}, year = {{2008}}, } @article{13673, author = {{Rakel, Munise and Cobet, Christoph and Esser, Norbert and Fuchs, Frank and Bechstedt, Friedhelm and Goldhahn, Rüdiger and Schmidt, Wolf Gero and Schaff, William}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{11}}, title = {{{GaN and InN conduction-band states studied by ellipsometry}}}, doi = {{10.1103/physrevb.77.115120}}, volume = {{77}}, year = {{2008}}, } @article{13669, author = {{Rauls, E. and Dijkstra, S. J. and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{11}}, title = {{{Atomic structure and energetics of thec-GaN(001) surface}}}, doi = {{10.1103/physrevb.78.113302}}, volume = {{78}}, year = {{2008}}, } @article{13670, author = {{Rauls, E. and Blankenburg, S. and Schmidt, Wolf Gero}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{2170--2174}}, title = {{{DFT calculations of adenine adsorption on coin metal (110) surfaces}}}, doi = {{10.1016/j.susc.2008.04.029}}, volume = {{602}}, year = {{2008}}, } @article{13675, author = {{Lange, B. and Schmidt, Wolf Gero}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{1207--1211}}, title = {{{Ammonia adsorption on Cl/Si(001): First-principles calculations}}}, doi = {{10.1016/j.susc.2008.01.024}}, volume = {{602}}, year = {{2008}}, } @article{13672, author = {{Hermann, A and Schwerdtfeger, P and Schmidt, Wolf Gero}}, issn = {{0953-8984}}, journal = {{Journal of Physics: Condensed Matter}}, title = {{{Theoretical study of the localization of excess electrons at the surface of ice}}}, doi = {{10.1088/0953-8984/20/22/225003}}, volume = {{20}}, year = {{2008}}, } @article{13668, author = {{Rauls, E. and Schmidt, Wolf Gero}}, issn = {{1932-7447}}, journal = {{Journal of Physical Chemistry C}}, pages = {{11490--11494}}, title = {{{Influence of the Side Group Aromaticity on the Organic Molecule Adsorption on Cu(110)}}}, doi = {{10.1021/jp8037297}}, volume = {{112}}, year = {{2008}}, } @article{13663, author = {{Wippermann, S. and Schmidt, Wolf Gero}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{247--250}}, title = {{{Optical anisotropy of the In/Si(111)(4×1)/(8×2) nanowire array}}}, doi = {{10.1016/j.susc.2008.11.013}}, volume = {{603}}, year = {{2008}}, } @article{13667, author = {{Blankenburg, S. and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, title = {{{Spatial modulation of molecular adsorption energies due to indirect interaction}}}, doi = {{10.1103/physrevb.78.233411}}, volume = {{78}}, year = {{2008}}, } @article{18564, abstract = {{In the context of photoelectron spectroscopy, the GW approach has developed into the method of choice for computing excitation spectra of weakly correlated bulk systems and their surfaces. To employ the established computational schemes that have been developed for three-dimensional crystals, two-dimensional systems are typically treated in the repeated-slab approach. In this work we critically examine this approach and identify three important aspects for which the treatment of long-range screening in two dimensions differs from the bulk: (1) anisotropy of the macroscopic screening, (2) k-point sampling parallel to the surface, (3) periodic repetition and slab-slab interaction. For prototypical semiconductor (silicon) and ionic (NaCl) thin films we quantify the individual contributions of points (1) to (3) and develop robust and efficient correction schemes derived from the classic theory of dielectric screening.}}, author = {{Freysoldt, Christoph and Eggert, Philipp and Rinke, Patrick and Schindlmayr, Arno and Scheffler, Matthias}}, issn = {{1550-235X}}, journal = {{Physical Review B}}, number = {{23}}, publisher = {{American Physical Society}}, title = {{{Screening in two dimensions: GW calculations for surfaces and thin films using the repeated-slab approach}}}, doi = {{10.1103/PhysRevB.77.235428}}, volume = {{77}}, year = {{2008}}, } @inproceedings{43266, abstract = {{In extreme nonlinear optics the Rabi frequency is comparable to or even larger than the transition frequency. Numerical solutions of the semiconductor Bloch equations show that the response of semiconductor quantum wells and wires differs characteristically from that of a two-level system in this highly nonperturbative regime. The main reason for these differences is the continuous electronic dispersion, and, to a lesser degree, the Coulombic interaction effects.}}, author = {{Golde, D. and Meier, Torsten and Koch, S.W.}}, booktitle = {{Ultrafast Phenomena XV: Proceedings of the 15th International Conference}}, location = {{Pacific Grove, USA}}, pages = {{689–691}}, publisher = {{Springer Berlin Heidelberg}}, title = {{{Modeling of the Extreme Nonlinear Optical Response of Semiconductor Nanostructures}}}, doi = {{10.1007/978-3-540-68781-8_221}}, volume = {{88}}, year = {{2007}}, } @article{43268, abstract = {{The combination of dielectric photonic crystals and semiconductor nanostructures makes it possible to design many important aspects of the optoelectronic system response. A spatially-varying dielectric environment induces modifications of the transversal and the longitudinal components of the electromagnetic field which have to be included in the self-consistent microscopic analysis of the optical properties of hybrid semiconductor photonic-crystal structures. In this paper, the development of a semiclassical microscopic theory is reviewed. Whereas the classical electromagnetic field is described at the level of Maxwell's equations, a full many-body quantum theory is used for the interacting electronic excitations in the semiconductor material. Relevant examples of the numerical solutions of the resulting Maxwell semiconductor Bloch equations are presented showing, e.g., characteristic modifications of excitonic absorption spectra, the spatio-temporal dynamics of electronic wave packets, as well as an increase of the optical gain in properly designed device geometries.}}, author = {{Pasenow, B. and Reichelt, Matthias and Stroucken, T. and Meier, Torsten and Koch, S.W.}}, journal = {{physica status solidi (a)}}, number = {{11}}, pages = {{3600--3617}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Microscopic analysis of the optical and electronic properties of semiconductor photonic‐crystal structures}}}, doi = {{10.1002/pssa.200776403}}, volume = {{204}}, year = {{2007}}, } @article{43267, abstract = {{The imaginary part of two-dimensional Fourier-transform spectra in the rephasing and nonrephasing modes is used to analyze the homogeneous and inhomogeneous broadening of excitonic resonances in semiconductor nanostructures. Microscopic calculations that include heavy- and light-hole excitons as well as coherent biexcitonic many-body correlations reveal distinct differences between the rephasing and nonrephasing spectra. A procedure is proposed that allows separation of disorder-induced broadening in complex systems that show several coupled resonances.}}, author = {{Kuznetsova, I. and Meier, Torsten and Cundiff, S.T. and Thomas, P. }}, journal = {{Physical Review B}}, number = {{15}}, publisher = {{American Physical Society}}, title = {{{Determination of homogeneous and inhomogeneous broadening in semiconductor nanostructures by two-dimensional Fourier-transform optical spectroscopy}}}, doi = {{10.1103/PhysRevB.76.153301}}, volume = {{76}}, year = {{2007}}, } @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}}, }