@article{25907,
  abstract     = {{<jats:p>The combined benefits of moisture-stable phosphonic acids and mesoporous silica materials (SBA-15 and MCM-41) as large-surface-area solid supports offer new opportunities for several applications, such as catalysis or drug delivery. We present a comprehensive study of a straightforward synthesis method via direct immobilization of several phosphonic acids and phosphoric acid esters on various mesoporous silicas in a Dean–Stark apparatus with toluene as the solvent. Due to the utilization of azeotropic distillation, there was no need to dry phosphonic acids, phosphoric acid esters, solvents, or silicas prior to synthesis. In addition to modeling phosphonic acids, immobilization of the important biomolecule adenosine monophosphate (AMP) on the porous supports was also investigated. Due to the high surface area of the mesoporous silicas, a possible catalytic application based on immobilization of an organocatalyst for an asymmetric aldol reaction is discussed.</jats:p>}},
  author       = {{Weinberger, Christian and Heckel, Tatjana and Schnippering, Patrick and Schmitz, Markus and Guo, Anpeng and Keil, Waldemar and Marsmann, Heinrich C. and Schmidt, Claudia and Tiemann, Michael and Wilhelm, René}},
  issn         = {{2079-4991}},
  journal      = {{Nanomaterials}},
  title        = {{{Straightforward Immobilization of Phosphonic Acids and Phosphoric Acid Esters on Mesoporous Silica and Their Application in an Asymmetric Aldol Reaction}}},
  doi          = {{10.3390/nano9020249}},
  year         = {{2019}},
}

@article{25904,
  abstract     = {{We examined the effect of CaCl2 and LiCl on ice melting in mesoporous silica (MCM-41 and SBA-15 silica). For that purpose, we determined the ice melting temperature in pores of various size (pore radii between 1.9 and 11.1 nm) in water and aqueous solutions up to high total solute molality (up to about 12 mol kg–1) using differential scanning calorimetry. We found that both electrolytes reduce the ice melting temperature within the pores. An exception is the melting of ice in the smallest pores, which does not seem to be affected by the presence of solutes, most likely owing to an exclusion of the ions from entering the pores. For all other pores, we observed that the ice melting temperature decreases as a function of pore size and electrolyte concentration. Using thermodynamic considerations as well as additional experimental data we developed a parametrization that can be used to predict the ice melting point as a function of pore size and total solute molality. For that purpose, we extended a formulation of the effective water activity of aqueous solutions under mechanical pressure toward its application in confinement and tested this new parametrization on literature data.}},
  author       = {{Jantsch, Evelyn and Weinberger, Christian and Tiemann, Michael and Koop, Thomas}},
  issn         = {{1932-7447}},
  journal      = {{The Journal of Physical Chemistry C}},
  pages        = {{24566--24574}},
  title        = {{{Phase Transitions of Ice in Aqueous Salt Solutions within Nanometer-Sized Pores}}},
  doi          = {{10.1021/acs.jpcc.9b06527}},
  year         = {{2019}},
}

@inproceedings{36934,
  author       = {{Lehmann, Tim and Büchel, Daniel and Cockcroft, John and Abegail Louw, Quinette and Baumeister, Jochen}},
  location     = {{Rom}},
  title        = {{{Phase Coupling of Bilateral Motor Areas Decreases from Bipedal to Single Leg Stance}}},
  year         = {{2019}},
}

@article{25905,
  abstract     = {{A nanocomposite material based on copper(II) oxide (CuO) and its utilization as a highly selective and stable gas-responsive electrical switch for hydrogen sulphide (H2S) detection is presented. The material can be applied as a sensitive layer for H2S monitoring, e.g., in biogas gas plants. CuO nanoparticles are embedded in a rigid, nanoporous silica (SiO2) matrix to form an electrical percolating network of low conducting CuO and, upon exposure to H2S, highly conducting copper(II) sulphide (CuS) particles. By steric hindrance due to the silica pore walls, the structure of the network is maintained even though the reversible reaction of CuO to CuS is accompanied by significant volume expansion. The conducting state of the percolating network can be controlled by a variety of parameters, such as temperature, electrode layout, and network topology of the porous silica matrix. The latter means that this new type of sensing material has a structure-encoded detection limit for H2S, which offers new application opportunities. The fabrication process of the mesoporous CuO@SiO2 composite as well as the sensor design and characteristics are described in detail. In addition, theoretical modeling of the percolation effect by Monte-Carlo simulations yields deeper insight into the underlying percolation mechanism and the observed response characteristics.}},
  author       = {{Paul, Andrej and Schwind, Bertram and Weinberger, Christian and Tiemann, Michael and Wagner, Thorsten}},
  issn         = {{1616-301X}},
  journal      = {{Advanced Functional Materials}},
  title        = {{{Gas Responsive Nanoswitch: Copper Oxide Composite for Highly Selective H2S Detection}}},
  doi          = {{10.1002/adfm.201904505}},
  year         = {{2019}},
}

@article{14544,
  author       = {{Vondran, J. and Spitzer, F. and Bayer, M. and Akimov, I. A. and Trautmann, Alexander and Reichelt, Matthias and Meier, Cedrik and Weber, N. and Meier, Torsten and André, R. and Mariette, H.}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{15}},
  pages        = {{155308}},
  title        = {{{Spatially asymmetric transients of propagating exciton-polariton modes in a planar CdZnTe/CdMgTe guiding structure}}},
  doi          = {{10.1103/physrevb.100.155308}},
  volume       = {{100}},
  year         = {{2019}},
}

@article{10014,
  abstract     = {{The cubic, tetragonal, and orthorhombic phase of potassium niobate (KNbO3) are studied based on density-functional theory. Starting from the relaxed atomic geometries, we analyze the influence of self-energy corrections on the electronic band structure within the GW approximation. We find that quasiparticle shifts widen the direct (indirect) band gap by 1.21 (1.44), 1.58 (1.55), and 1.67 (1.64) eV for the cubic, tetragonal, and orthorhombic phase, respectively. By solving the Bethe-Salpeter equation, we obtain the linear dielectric function with excitonic and local-field effects, which turn out to be essential for good agreement with experimental data. From our results, we extract an exciton binding energy of 0.6, 0.5, and 0.5 eV for the cubic, tetragonal, and orthorhombic phase, respectively. Furthermore, we investigate the nonlinear second-harmonic generation (SHG) both theoretically and experimentally. The frequency-dependent second-order polarization tensor of orthorhombic KNbO3 is measured for incoming photon energies between 1.2 and 1.6 eV. In addition, calculations within the independent-(quasi)particle approximation are performed for the tetragonal and orthorhombic phase. The novel experimental data are in excellent agreement with the quasiparticle calculations and resolve persistent discrepancies between earlier experimental measurements and ab initio results reported in the literature.}},
  author       = {{Schmidt, Falko and Riefer, Arthur and Schmidt, Wolf Gero and Schindlmayr, Arno and Imlau, Mirco and Dobener, Florian and Mengel, Nils and Chatterjee, Sangam and Sanna, Simone}},
  issn         = {{2475-9953}},
  journal      = {{Physical Review Materials}},
  number       = {{5}},
  publisher    = {{American Physical Society}},
  title        = {{{Quasiparticle and excitonic effects in the optical response of KNbO3}}},
  doi          = {{10.1103/PhysRevMaterials.3.054401}},
  volume       = {{3}},
  year         = {{2019}},
}

@article{29746,
  author       = {{Nicholson, C. W. and Puppin, M. and Lücke, A. and Gerstmann, Uwe and Krenz, Marvin and Schmidt, Wolf Gero and Rettig, L. and Ernstorfer, R. and Wolf, M.}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{15}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Excited-state band mapping and momentum-resolved ultrafast population dynamics in In/Si(111) nanowires investigated with XUV-based time- and angle-resolved photoemission spectroscopy}}},
  doi          = {{10.1103/physrevb.99.155107}},
  volume       = {{99}},
  year         = {{2019}},
}

@article{10015,
  author       = {{Dues, Christof and Schmidt, Wolf Gero and Sanna, Simone}},
  issn         = {{2470-1343}},
  journal      = {{ACS Omega}},
  pages        = {{3850--3859}},
  title        = {{{Water Splitting Reaction at Polar Lithium Niobate Surfaces}}},
  doi          = {{10.1021/acsomega.8b03271}},
  year         = {{2019}},
}

@article{26296,
  author       = {{Sperling, Jan and Perez-Leija, Armando and Busch, Kurt and Silberhorn, Christine}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  title        = {{{Mode-independent quantum entanglement for light}}},
  doi          = {{10.1103/physreva.100.062129}},
  year         = {{2019}},
}

@article{37288,
  abstract     = {{<jats:p>An integrated chip with quantum state generation, active polarization manipulation, and precise time control is demonstrated.</jats:p>}},
  author       = {{Luo, Kai-Hong and Brauner, Sebastian and Eigner, Christof and Sharapova, Polina and Ricken, Raimund and Meier, Torsten and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{2375-2548}},
  journal      = {{Science Advances}},
  keywords     = {{Multidisciplinary}},
  number       = {{1}},
  publisher    = {{American Association for the Advancement of Science (AAAS)}},
  title        = {{{Nonlinear integrated quantum electro-optic circuits}}},
  doi          = {{10.1126/sciadv.aat1451}},
  volume       = {{5}},
  year         = {{2019}},
}

@inproceedings{13285,
  author       = {{Hannes, Wolf-Rüdiger and Krauß-Kodytek, Laura and Ruppert, Claudia and Betz, Markus and Meier, Torsten}},
  booktitle    = {{Ultrafast Phenomena and Nanophotonics XXIII}},
  editor       = {{Betz, Markus and Elezzabi, Abdulhakem Y.}},
  isbn         = {{9781510624740}},
  title        = {{{Intensity-dependent degenerate and non-degenerate nonlinear optical absorption of direct-gap semiconductors}}},
  doi          = {{10.1117/12.2503539}},
  volume       = {{10916}},
  year         = {{2019}},
}

@article{13284,
  author       = {{Hannes, Wolf-Rüdiger and Meier, Torsten}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{12}},
  title        = {{{Higher-order contributions and nonperturbative effects in the nondegenerate nonlinear optical absorption of semiconductors using a two-band model}}},
  doi          = {{10.1103/physrevb.99.125301}},
  volume       = {{99}},
  year         = {{2019}},
}

@article{13365,
  abstract     = {{The KTiOPO4 (KTP) band structure and dielectric function are calculated on various levels of theory starting from density-functional calculations. Within the independent-particle approximation an electronic transport gap of 2.97 eV is obtained that widens to about 5.23 eV when quasiparticle effects are included using the GW approximation. The optical response is shown to be strongly anisotropic due to (i) the slight asymmetry of the TiO6 octahedra in the (001) plane and (ii) their anisotropic distribution along the [001] and [100] directions. In addition, excitonic effects are very important: The solution of the Bethe–Salpeter equation indicates exciton binding energies of the order of 1.5 eV. Calculations that include both quasiparticle and excitonic effects are in good agreement with the measured reflectivity.}},
  author       = {{Neufeld, Sergej and Bocchini, Adriana and Gerstmann, Uwe and Schindlmayr, Arno and Schmidt, Wolf Gero}},
  issn         = {{2515-7639}},
  journal      = {{Journal of Physics: Materials}},
  pages        = {{045003}},
  publisher    = {{IOP Publishing}},
  title        = {{{Potassium titanyl phosphate (KTP) quasiparticle energies and optical response}}},
  doi          = {{10.1088/2515-7639/ab29ba}},
  volume       = {{2}},
  year         = {{2019}},
}

@article{25908,
  abstract     = {{Herein we present a new proton-conducting iron(II) metal–organic framework (MOF) of an unusual structure formed by chains of alternating bistriazolate-p-benzoquinone anions and iron(II) cations with four axially coordinated water molecules. These chains assemble via π–π stacking between the aromatic units to form a three-dimensional grid-like network with channel pores filled with water molecules. The material was structurally characterized by single-crystal XRD analysis, and its water and thermal stability was investigated. The proton conductivity was studied by impedance measurements on needle-like single crystals. A simple but efficient measurement setup consisting of interdigital electrodes was used. The influence of the crystal orientation, temperature, and humidity was investigated. The iron(II)-MOF showed the highest proton conductivity of 3.3·10–3 S cm–1 at 22 °C and 94% relative humidity. Contrary to most known structures, the conductivity in this material is controlled by chemical properties of the pore system rather than by grain boundaries. The presented material is the starting point for further tailoring the proton-conducting properties, independent of morphological features which could find potential applications as membrane materials in proton-exchange membrane fuel cells.}},
  author       = {{Bunzen, Hana and Javed, Ali and Klawinski, Danielle and Lamp, Anton and Grzywa, Maciej and Kalytta-Mewes, Andreas and Tiemann, Michael and von Nidda, Hans-Albrecht Krug and Wagner, Thorsten and Volkmer, Dirk}},
  issn         = {{2574-0970}},
  journal      = {{ACS Applied Nano Materials}},
  pages        = {{291--298}},
  title        = {{{Anisotropic Water-Mediated Proton Conductivity in Large Iron(II) Metal–Organic Framework Single Crystals for Proton-Exchange Membrane Fuel Cells}}},
  doi          = {{10.1021/acsanm.8b01902}},
  year         = {{2019}},
}

@article{25906,
  abstract     = {{A composite material of copper oxide (CuO) dispersed in the nanopores of KIT-6 silica (SiO2) is used as a dosimetric sensor for the detection of hydrogen sulfide (H2S) gas in low parts per milion concentrations. The sensor principle is based on the reversible chemical conversion of CuO to CuS, which guarantees a high selectivity, and on the corresponding percolation-induced change in electronic conductance.}},
  author       = {{Paul, Andrej and Weinberger, Christian and Tiemann, Michael and Wagner, Thorsten}},
  issn         = {{2574-0970}},
  journal      = {{ACS Applied Nano Materials}},
  pages        = {{3335--3338}},
  title        = {{{Copper Oxide/Silica Nanocomposites for Selective and Stable H2S Gas Detection}}},
  doi          = {{10.1021/acsanm.9b01004}},
  year         = {{2019}},
}

@article{26300,
  author       = {{Sperling, Jan and Meyer-Scott, E. and Barkhofen, Sonja and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  title        = {{{Experimental Reconstruction of Entanglement Quasiprobabilities}}},
  doi          = {{10.1103/physrevlett.122.053602}},
  year         = {{2019}},
}

@inproceedings{43748,
  abstract     = {{The fundamental interband absorption in gallium arsenide shows a strong blue shift when biased by mid-infrared transients exceeding 10 MV/cm. This subcycle feature is induced by the localization of electronic wavefunctions from 3D to 2D.}},
  author       = {{Meier, Torsten and Bühler, Johannes and Schmidt, Christian and Heinrich, Alexander-Cornelius and Allerbeck, Jonas and Podzimski, Reinold and Berghoff, Daniel and Schmidt, Wolf Gero and Reichl, Christian and Wegscheider, Werner and Brida, Daniele and Leitenstorfer, Alfred}},
  booktitle    = {{XXI International Conference on Ultrafast Phenomena 2018 (UP 2018)}},
  publisher    = {{EDP Sciences}},
  title        = {{{Subcycle Wannier-Stark Localization by Mid-Infrared Bias in Gallium Arsenide}}},
  doi          = {{10.1051/epjconf/201920505001}},
  volume       = {{205}},
  year         = {{2019}},
}

@article{22887,
  author       = {{Vondran, J. and Spitzer, F. and Bayer, M. and Akimov, I. A. and Trautmann, Alexander and Reichelt, Matthias and Meier, Cedrik and Weber, N. and Meier, Torsten and André, R. and Mariette, H.}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{15}},
  pages        = {{155308}},
  title        = {{{Spatially asymmetric transients of propagating exciton-polariton modes in a planar CdZnTe/CdMgTe guiding structure}}},
  doi          = {{10.1103/physrevb.100.155308}},
  volume       = {{100}},
  year         = {{2019}},
}

@unpublished{22884,
  abstract     = {{Measurement-induced nonclassical effects in a two-mode interferometer are
investigated theoretically using numerical simulations and analytical results.
We demonstrate that for certain parameters measurements within the
interferometer lead to the occurrence of two-mode squeezing. The results
strongly depend on the detection probability, the phase inside the
interferometer, and the choice of the input states. The appropriate parameters
for maximized squeezing are obtained. We analyze the influence of losses and
confirm that the predicted effects are within reach of current experimental
techniques.}},
  author       = {{Riabinin, Matvei and Sharapova, Polina and Bartley, Tim and Meier, Torsten}},
  booktitle    = {{arXiv:1912.09097}},
  title        = {{{Generating two-mode squeezing with multimode measurement-induced nonlinearity}}},
  year         = {{2019}},
}

@article{13900,
  author       = {{Song, Xiaohong and Zuo, Ruixin and Yang, Shidong and Li, Pengcheng and Meier, Torsten and Yang, Weifeng}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  number       = {{3}},
  pages        = {{2225--2234}},
  title        = {{{Attosecond temporal confinement of interband excitation by intraband motion}}},
  doi          = {{10.1364/oe.27.002225}},
  volume       = {{27}},
  year         = {{2019}},
}