@article{26889, author = {{Luo, Kai Hong and Santandrea, Matteo and Stefszky, Michael and Sperling, Jan and Massaro, Marcello and Ferreri, Alessandro and Sharapova, Polina and Herrmann, Harald and Silberhorn, Christine}}, issn = {{2469-9926}}, journal = {{Physical Review A}}, title = {{{Quantum optical coherence: From linear to nonlinear interferometers}}}, doi = {{10.1103/physreva.104.043707}}, year = {{2021}}, } @article{26283, author = {{Lüders, Carolin and Pukrop, Matthias and Rozas, Elena and Schneider, Christian and Höfling, Sven and Sperling, Jan and Schumacher, Stefan and Aßmann, Marc}}, issn = {{2691-3399}}, journal = {{PRX Quantum}}, title = {{{Quantifying Quantum Coherence in Polariton Condensates}}}, doi = {{10.1103/prxquantum.2.030320}}, year = {{2021}}, } @article{26284, author = {{Bagrets, Dmitry and Kim, Kun Woo and Barkhofen, Sonja and De, Syamsundar and Sperling, Jan and Silberhorn, Christine and Altland, Alexander and Micklitz, Tobias}}, issn = {{2643-1564}}, journal = {{Physical Review Research}}, title = {{{Probing the topological Anderson transition with quantum walks}}}, doi = {{10.1103/physrevresearch.3.023183}}, year = {{2021}}, } @article{21362, author = {{Xue, Yan and Chestnov, Igor and Sedov, Evgeny and Kiktenko, Evgeniy and Fedorov, Aleksey K. and Schumacher, Stefan and Ma, Xuekai and Kavokin, Alexey}}, issn = {{2643-1564}}, journal = {{Physical Review Research}}, number = {{1}}, title = {{{Split-ring polariton condensates as macroscopic two-level quantum systems}}}, doi = {{10.1103/physrevresearch.3.013099}}, volume = {{3}}, year = {{2021}}, } @article{29747, author = {{Jurgen von Bardeleben, Hans and Cantin, Jean-Louis and Gerstmann, Uwe and Schmidt, Wolf Gero and Biktagirov, Timur}}, issn = {{1530-6984}}, journal = {{Nano Letters}}, keywords = {{Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}}, number = {{19}}, pages = {{8119--8125}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Spin Polarization, Electron–Phonon Coupling, and Zero-Phonon Line of the NV Center in 3C-SiC}}}, doi = {{10.1021/acs.nanolett.1c02564}}, volume = {{21}}, year = {{2021}}, } @article{29748, author = {{Slawig, Diana and Gruschwitz, Markus and Gerstmann, Uwe and Rauls, Eva and Tegenkamp, Christoph}}, issn = {{1932-7447}}, journal = {{The Journal of Physical Chemistry C}}, keywords = {{Surfaces, Coatings and Films, Physical and Theoretical Chemistry, General Energy, Electronic, Optical and Magnetic Materials}}, number = {{36}}, pages = {{20087--20093}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Adsorption and Reaction of PbPc on Hydrogenated Epitaxial Graphene}}}, doi = {{10.1021/acs.jpcc.1c06320}}, volume = {{125}}, year = {{2021}}, } @article{40250, author = {{Jain, Mitisha and Gerstmann, Uwe and Schmidt, Wolf Gero and Aldahhak, Hazem}}, issn = {{0192-8651}}, journal = {{Journal of Computational Chemistry}}, keywords = {{Computational Mathematics, General Chemistry}}, number = {{6}}, pages = {{413--420}}, publisher = {{Wiley}}, title = {{{Adatom mediated adsorption of N‐heterocyclic carbenes on Cu(111) and Au(111)}}}, doi = {{10.1002/jcc.26801}}, volume = {{43}}, year = {{2021}}, } @article{37331, abstract = {{High harmonic generation (HHG) from solids shows great application prospects in compact short-wavelength light sources and as a tool for imaging the dynamics in crystals with subnanometer spatial and attosecond temporal resolution. However, the underlying collision dynamics behind solid HHG is still intensively debated and no direct mapping relationship between the collision dynamics with band structure has been built. Here, we show that the electron and its associated hole can be elastically scattered by neighboring atoms when their wavelength approaches the atomic size. We reveal that the elastic scattering of electron/hole from neighboring atoms can dramatically influence the electron recombination with its left-behind hole, which turns out to be the fundamental reason for the anisotropic interband HHG observed recently in bulk crystals. Our findings link the electron/hole backward scattering with Van Hove singularities and forward scattering with critical lines in the band structure and thus build a clear mapping between the band structure and the harmonic spectrum. Our work provides a unifying picture for several seemingly unrelated experimental observations and theoretical predictions, including the anisotropic harmonic emission in MgO, the atomic-like recollision mechanism of solid HHG, and the delocalization of HHG in ZnO. This strongly improved understanding will pave the way for controlling the solid-state HHG and visualizing the structure-dependent electron dynamics in solids.}}, author = {{Zuo, Ruixin and Trautmann, Alexander and Wang, Guifang and Hannes, Wolf-Rüdiger and Yang, Shidong and Song, Xiaohong and Meier, Torsten and Ciappina, Marcelo and Duc, Huynh Thanh and Yang, Weifeng}}, issn = {{2765-8791}}, journal = {{Ultrafast Science}}, publisher = {{American Association for the Advancement of Science (AAAS)}}, title = {{{Neighboring Atom Collisions in Solid-State High Harmonic Generation}}}, doi = {{10.34133/2021/9861923}}, volume = {{2021}}, year = {{2021}}, } @article{37338, abstract = {{AbstractMethylammonium lead iodide perovskite (MAPbI3) is renowned for an impressive power conversion efficiency rise and cost-effective fabrication for photovoltaics. In this work, we demonstrate that polycrystalline MAPbI3s undergo drastic changes in optical properties at moderate field strengths with an ultrafast response time, via transient Wannier Stark localization. The distinct band structure of this material - the large lattice periodicity, the narrow electronic energy bandwidths, and the coincidence of these two along the same high-symmetry direction – enables relatively weak fields to bring this material into the Wannier Stark regime. Its polycrystalline nature is not detrimental to the optical switching performance of the material, since the least dispersive direction of the band structure dominates the contribution to the optical response, which favors low-cost fabrication. Together with the outstanding photophysical properties of MAPbI3, this finding highlights the great potential of this material in ultrafast light modulation and novel photonic applications.}}, author = {{Berghoff, Daniel and Bühler, Johannes and Bonn, Mischa and Leitenstorfer, Alfred and Meier, Torsten and Kim, Heejae}}, issn = {{2041-1723}}, journal = {{Nature Communications}}, keywords = {{General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Low-field onset of Wannier-Stark localization in a polycrystalline hybrid organic inorganic perovskite}}}, doi = {{10.1038/s41467-021-26021-4}}, volume = {{12}}, year = {{2021}}, } @article{23477, author = {{Thong, Le Huu and Ngo, Cong and Duc, Huynh Thanh and Song, Xiaohong and Meier, Torsten}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{085201}}, title = {{{Microscopic analysis of high harmonic generation in semiconductors with degenerate bands}}}, doi = {{10.1103/physrevb.103.085201}}, volume = {{103}}, year = {{2021}}, } @article{21946, abstract = {{Lithium niobate (LiNbO3), a material frequently used in optical applications, hosts different kinds of polarons that significantly affect many of its physical properties. In this study, a variety of electron polarons, namely free, bound, and bipolarons, are analyzed using first-principles calculations. We perform a full structural optimization based on density-functional theory for selected intrinsic defects with special attention to the role of symmetry-breaking distortions that lower the total energy. The cations hosting the various polarons relax to a different degree, with a larger relaxation corresponding to a larger gap between the defect level and the conduction-band edge. The projected density of states reveals that the polaron states are formerly empty Nb 4d states lowered into the band gap. Optical absorption spectra are derived within the independent-particle approximation, corrected by the GW approximation that yields a wider band gap and by including excitonic effects within the Bethe-Salpeter equation. Comparing the calculated spectra with the density of states, we find that the defect peak observed in the optical absorption stems from transitions between the defect level and a continuum of empty Nb 4d states. Signatures of polarons are further analyzed in the reflectivity and other experimentally measurable optical coefficients.}}, author = {{Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}}, issn = {{2073-4352}}, journal = {{Crystals}}, pages = {{542}}, publisher = {{MDPI}}, title = {{{Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}}}, doi = {{10.3390/cryst11050542}}, volume = {{11}}, year = {{2021}}, } @inproceedings{43746, abstract = {{Population/mixing-time-dependent two-dimensional coherent spectra are presented for exciton-polaritons in a microcavity. Theory based on dynamically-controlled truncation reveals coherent and incoherent contributions to the decay dynamics.}}, author = {{Meier, Torsten and Paul, Jagannath and Rose, Hendrik and Wahlstrand, Jared K and Bristow, Alan D}}, booktitle = {{Frontiers in Optics}}, isbn = {{978-1-55752-308-2}}, location = {{Washington, DC United States}}, publisher = {{Frontiers in Optics}}, title = {{{Coherent and incoherent contribution of population dynamics of semiconductor exciton-polaritons}}}, doi = {{10.1364/FIO.2021.FW5C.6}}, year = {{2021}}, } @inproceedings{23474, author = {{Reichelt, Matthias and Rose, Hendrik and Kosarev, Alexander N. and Poltavtsev, Sergey V. and Bayer, Manfred and Akimov, Ilya A. and Schneider, Christian and Kamp, Martin and Höfling, Sven and Meier, Torsten}}, booktitle = {{Ultrafast Phenomena and Nanophotonics XXV}}, editor = {{Betz, Markus and Elezzabi, Abdulhakem Y.}}, title = {{{Controlling the emission time of photon echoes by optical freezing of exciton dephasing and rephasing in quantum-dot ensembles}}}, doi = {{10.1117/12.2576887}}, volume = {{11684}}, year = {{2021}}, } @article{29749, author = {{Murzakhanov, F. F. and Yavkin, B. V. and Mamin, G. V. and Orlinskii, S. B. and von Bardeleben, H. J. and Biktagirov, Timur and Gerstmann, Uwe and Soltamov, V. A.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{245203}}, publisher = {{American Physical Society (APS)}}, title = {{{Hyperfine and nuclear quadrupole splitting of the NV− ground state in 4H-SiC}}}, doi = {{10.1103/physrevb.103.245203}}, volume = {{103}}, year = {{2021}}, } @article{22010, author = {{Aldahhak, Hazem and Hogan, Conor and Lindner, Susi and Appelfeller, Stephan and Eisele, Holger and Schmidt, Wolf Gero and Dähne, Mario and Gerstmann, Uwe and Franz, Martin}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{035303}}, title = {{{Electronic structure of the Si(111)3×3R30∘−B surface from theory and photoemission spectroscopy}}}, doi = {{10.1103/physrevb.103.035303}}, volume = {{103}}, year = {{2021}}, } @article{23478, author = {{Rose, Hendrik and Popolitova, D. V. and Tikhonova, O. V. and Meier, Torsten and Sharapova, Polina}}, issn = {{2469-9926}}, journal = {{Physical Review A}}, title = {{{Dark-state and loss-induced phenomena in the quantum-optical regime of Λ-type three-level systems}}}, doi = {{10.1103/physreva.103.013702}}, volume = {{103}}, year = {{2021}}, } @article{23473, author = {{Belobo, Didier Belobo and Meier, Torsten}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Approximate nonlinear wave solutions of the coupled two-component Gross–Pitaevskii equations with spin–orbit interaction}}}, doi = {{10.1088/1367-2630/abf3ed}}, volume = {{23}}, year = {{2021}}, } @article{22881, author = {{Nguyen, T. T. Nhung and Sollfrank, T. and Tegenkamp, C. and Rauls, E. and Gerstmann, Uwe}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, pages = {{L201408}}, title = {{{Impact of screening and relaxation on weakly coupled two-dimensional heterostructures}}}, doi = {{10.1103/physrevb.103.l201408}}, volume = {{103}}, year = {{2021}}, } @article{21635, abstract = {{Modern forming processes often allow today the efficient production of complex parts. In order to increase the sustainability of forming processes it would be favorable if the forming of workpieces becomes possible using production waste. At the Chair of Forming and Machining Technology of the Paderborn University (LUF) research is presently conducted with the overall goal to produce workpieces directly from secondary aluminum (e.g., powder and chips). Therefore, friction-based forming processes like friction spinning (or cognate processes) are used due to their high efficiency. As a pre-step, the production of semi-finished parts was the subject of accorded research work at the LUF. Therefore, a friction-based hot extrusion process was used for the full recycling or rework of aluminum chips into profiles. Investigations of the recycled semi-finished products show that they are comparable to conventionally produced semi-finished products in terms of dimensional stability and shape accuracy. An analysis of the mechanical properties of hardness and tensile strength shows that a final product with good and homogeneously distributed properties can be produced. Furthermore, significant correlations to the friction spinning process could be found that are useful for the above-mentioned direct part production from secondary aluminum.}}, author = {{Borgert, Thomas and Homberg, Werner}}, issn = {{2075-4701}}, journal = {{Metals}}, title = {{{Friction-Induced Recycling Process for User-Specific Semi-Finished Product Production}}}, doi = {{10.3390/met11040663}}, year = {{2021}}, } @inproceedings{23746, author = {{Moritzer, Elmar and Flachmann, Felix}}, booktitle = {{SPE ANTEC 2021: The Annual Technical Conference for Plastic Professionals}}, isbn = {{978-1-7138-3075-7}}, location = {{Online}}, pages = {{536--540}}, title = {{{Influence of Chemical Blowing Agents on the Filling Behavior of Wood-Plastic-Composite Melts}}}, year = {{2021}}, }