News
| December 2012 | |
The fellowship will support Lijian's research plan on coherent control of cuprate high-temperature superconductors with quantum-optical methods. The work will not only have an impact on fundamental studies of high-Tc superconductors but also shed light on fabricating quantum devices with such materials. |
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| Nov.2012, new publication in Nature Photonics: Ultrafast X-ray pulse characterization at free-electron lasers |
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| Aug.2012, new publication in PRB: |
| June 2012: | ||
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| Info: The Rashba-Bychkov effect describes how the spin-degeneracy in different two-dimensional systems such as quantum well states in semiconductor heterojunctions or surface states on noble metal surfaces can be lifted by the spin-orbit interaction in case of a broken space inversion symmetry. The resulting band structure consists of two nearly parabolic bands with opposite spin-polarization that cross at time-reversal invariant points of the Brillouin zone. Such a spin-polarized band structure bares great potential for applications as a spin field effect transistor. Furthermore, theoretical predictions for a superconducting state have been made, and these systems are prime candidates for the observation of the spin Hall effect. Different two-dimensional systems are best compared using the so-called Rashba-parameter, a measure for the size of the spin splitting. The biggest spin splitting measured so far has been detected in two-dimensional bismuth-silver surface alloys. There, the giant spin splitting can be traced back to (1) the presence of heavy atoms with a strong spin-orbit coupling and (2) the corrugation of the two-dimensional alloy that leads to a strong asymmetry of the electron cloud in the vicinity of the nucleus. However, the application of these surface alloys in a spin field effect transistor is prevented by the presence of spin-degenerate three-dimensional states from the silver substrate. In collaboration with scientists at the Max Planck Institute for Solid State Research in Stuttgart and the Max Planck Institute for Microstructure Physics in Halle, Isabella Gierz was able to transfer the concept of a giant spin splitting to a semiconducting silicon substrate [see Physical Review Letters 103, 046803 (2009)]. For the discovery of a giant spin splitting on the surface of a semiconductor Isabella Gierz has now received the Otto Hahn Award of the Max Planck Society. | ||
| Mar. 2012: New publication in PRL: Ultrafast Strain Engineering in Complex Oxide Heterostructures |
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| Nov. 2011: New publication in Optics Letters: Coherent single-cycle pulses with MV/cm field strengths from a relativistic transition radiation light source |
Oct. 2011: New publication in PRL: Clocking the Melting Transition of Charge and Lattice Order in 1T-TaS2 with Ultrafast Extreme-Ultraviolet Angle-Resolved Photoemission Spectroscopy |
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| Oct. 2011: | Theory of correlated systems out of equilibrium group established, Martin Eckstein joined CFEL |
| Sept. 2011: | Dynamics of nanoelectronic systems group established, Sebastian Loth joined CFEL/MPSD |
Aug. 2011, |
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July 2011: June 2011, |
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| May 2011, new publication in PRL: Photoinduced Melting of Antiferromagnetic Order in La0.5Sr1.5MnO4 Measured Using Ultrafast Resonant Soft X-Ray Diffraction |
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| Mar. 2011: "Schlagartig widerstandslos", Interview with Andrea Cavalleri in Deutschlandfunk ⇒ podcast and text |
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| Jan. 2011, new publication in Nature Materials: Transient photoinduced ‘hidden’ phase in a manganite |
| Jan. 2011, new publication in Science: Light induced superconductivity in a stripe-oredered cuprate → more |
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| Jan. 2011, new publication in PRL: Polaronic conductivity in the photoinduced phase of 1T-TaS2 → more |
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| Dez. 2010: new publication online in Nature Physics: Quantum interference between charge excitation paths in a solid state Mott insulator → more |
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| January 2010, new publication in Optics letters: Single-Shot detection and direct control of carrier phase drift of mid-IR pulses. See a summary in the research section: Generation of carrier-envelope phase-stabilized pulses in the mid-IR |
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| January 2010, new publication in Appl. Phys. Lett.: Ultrafast insulator-to-metal phase transition as a switch to measure the spectrogram of a supercontinuum light pulse |
| October 2009, new publication in Phys.Rev.B: |
| Transient electronic structure of the photoinduced phase of Pr0.7Ca0.3MnO3 probed with soft x-ray pulses M. Rini et. al., Phys. Rev. B 80, 155113 (2009) --> more |
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August 2009, new publication in Phys. Rev. Lett. : S. Wall et. al., Phys. Rev. Lett. 103, 097402 (2009) --> more |
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On July 3rd, 2009, the Excellence Cluster “Frontiers in Quantum Photon Science” has been founded as new and highly profiled research activity within the framework of the excellence initiative of the federal state of Hamburg. The Cluster combines the expertise from laser-physics, quantum optics, short-time- and X-ray-physics as well as condensed matter physics. It thus brings together the photon science activities from the University, DESY and the Max-Planck research groups at Hamburg University in terms of research and education. For more details please visit the Cluster website: http://www.physnet.uni-hamburg.de/lexi/ |
| 5.March 2009: Melting in a Flash. Nature News & Views by Andrea Cavalleri |
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