TY - JOUR AU - von Bardeleben, H. J. AU - Rauls, E. AU - Gerstmann, Uwe ID - 40444 IS - 18 JF - Physical Review B SN - 2469-9950 TI - Carbon vacancy-related centers in 3C-silicon carbide: Negative-U properties and structural transformation VL - 101 ER - TY - JOUR AB -

EPR spectroscopy reveals the universality class and dynamic effects of the [NH4][Zn(HCOO)3] hybrid formate framework.

AU - Navickas, Marius AU - Giriūnas, Laisvydas AU - Kalendra, Vidmantas AU - Biktagirov, Timur AU - Gerstmann, Uwe AU - Schmidt, Wolf Gero AU - Mączka, Mirosław AU - Pöppl, Andreas AU - Banys, Jūras AU - Šimėnas, Mantas ID - 17070 JF - Physical Chemistry Chemical Physics SN - 1463-9076 TI - Electron paramagnetic resonance study of ferroelectric phase transition and dynamic effects in a Mn2+ doped [NH4][Zn(HCOO)3] hybrid formate framework VL - 22 ER - TY - JOUR AU - Biktagirov, Timur AU - Gerstmann, Uwe ID - 29745 IS - 2 JF - Physical Review Research KW - General Engineering SN - 2643-1564 TI - Spin-orbit driven electrical manipulation of the zero-field splitting in high-spin centers in solids VL - 2 ER - TY - JOUR AB - Density-functional theory calculations of (TiO2)n clusters (n = 1–5) in the gas phase and adsorbed on pristine graphene as well as graphene quantum dots are presented. The cluster adsorption is found to be dominated by van der Waals forces. The electronic structure and in particular the excitation energies of the bare clusters and the TiO2/graphene composites are found to vary largely in dependence on the size of the respective constituents. This holds in particular for the energy and the spatial localization of the highest occupied and lowest unoccupied molecular orbitals. In addition to a substantial gap narrowing, a pronounced separation of photoexcited electrons and holes is predicted in some instances. This is expected to prolong the lifetime of photoexcited carriers. Altogether, TiO2/graphene composites are predicted to be promising photocatalysts with improved electronic and photocatalytic properties compared to bulk TiO2. AU - Badalov, Sabuhi AU - Wilhelm, René AU - Schmidt, Wolf Gero ID - 19189 JF - Journal of Computational Chemistry SN - 0192-8651 TI - Photocatalytic properties of graphene‐supported titania clusters from density‐functional theory ER - TY - JOUR AB - AbstractSemiconductor quantum dots are excellent candidates for ultrafast coherent manipulation of qubits by laser pulses on picosecond timescales or even faster. In inhomogeneous ensembles a macroscopic optical polarization decays rapidly due to dephasing, which, however, is reversible in photon echoes carrying complete information about the coherent ensemble dynamics. Control of the echo emission time is mandatory for applications. Here, we propose a concept to reach this goal. In a two-pulse photon echo sequence, we apply an additional resonant control pulse with multiple of 2π area. Depending on its arrival time, the control slows down dephasing or rephasing of the exciton ensemble during its action. We demonstrate for self-assembled (In,Ga)As quantum dots that the photon echo emission time can be retarded or advanced by up to 5 ps relative to its nominal appearance time without control. This versatile protocol may be used to obtain significantly longer temporal shifts for suitably tailored control pulses. AU - Kosarev, Alexander N. AU - Rose, Hendrik AU - Poltavtsev, Sergey V. AU - Reichelt, Matthias AU - Schneider, Christian AU - Kamp, Martin AU - Höfling, Sven AU - Bayer, Manfred AU - Meier, Torsten AU - Akimov, Ilya A. ID - 20773 IS - 1 JF - Communications Physics SN - 2399-3650 TI - Accurate photon echo timing by optical freezing of exciton dephasing and rephasing in quantum dots VL - 3 ER - TY - JOUR AB - Vortices are topological objects representing the circular motion of a fluid. With their additional degree of freedom, the vorticity, they have been widely investigated in many physical systems and different materials for fundamental interest and for applications in data storage and information processing. Vortices have also been observed in non-equilibrium exciton-polariton condensates in planar semiconductor microcavities. There they appear spontaneously or can be created and pinned in space using ring-shaped optical excitation profiles. However, using the vortex state for information processing not only requires creation of a vortex but also efficient control over the vortex after its creation. Here we demonstrate a simple approach to control and switch a localized polariton vortex between opposite states. In our scheme, both the optical control of vorticity and its detection through the orbital angular momentum of the emitted light are implemented in a robust and practical manner. AU - Meier, Torsten AU - Ma, Xuekai AU - Berger, Bernd AU - Aßmann, Marc AU - Driben, Rodislav AU - Schneider, Christian AU - Höfling, Sven AU - Schumacher, Stefan ID - 43747 IS - 1 JF - Nature communications TI - Realization of all-optical vortex switching in exciton-polariton condensates VL - 11 ER - TY - CONF AU - Hannes, Wolf-Rüdiger AU - Meier, Torsten ED - Betz, Markus ED - Elezzabi, Abdulhakem Y. ID - 20770 SN - 9781510633193 T2 - Ultrafast Phenomena and Nanophotonics XXIV TI - k.p-based multiband simulations of non-degenerate two-photon absorption in bulk GaAs VL - 11278 ER - TY - JOUR AU - Hannes, W.-R. AU - Trautmann, Alexander AU - Stein, M. AU - Schäfer, F. AU - Koch, M. AU - Meier, Torsten ID - 20563 IS - 7 JF - Physical Review B TI - Strongly nonresonant four-wave mixing in semiconductors VL - 101 ER - TY - JOUR AU - Song, Xiaohong AU - Yang, Shidong AU - Zuo, Ruixin AU - Meier, Torsten AU - Yang, Weifeng ID - 20772 JF - Physical Review A SN - 2469-9926 TI - Enhanced high-order harmonic generation in semiconductors by excitation with multicolor pulses VL - 101 ER - TY - JOUR AU - Bocchini, Adriana AU - Eigner, Christof AU - Silberhorn, Christine AU - Schmidt, Wolf Gero AU - Gerstmann, Uwe ID - 20682 JF - Phys. Rev. Materials TI - Understanding gray track formation in KTP: Ti^3+ centers studied from first principles VL - 4 ER -