Dr. Clemens von Korff Schmising
The physicist's PhD thesis in ultrafast X-ray science was awarded the Lise-Meitner-Preis 2009
Clemens von Korff Schmising was born in 1977 in the Rhineland where he also grew up. After his ‘Vordiplom’ (BA) in Bayreuth, Bavaria and a stay abroad in St. Andrews in Scotland he returned to Bonn, where in the framework of this Diploma thesis he started to experiment with ultrashort laser pulses.
His interest in nonlinear optics lead him to postgraduate work at the Universities of Sydney and Auckland, before he decided to commence a PhD thesis in ultrafast X-ray science with Professor Thomas Elsässer at the Max-Born-Institute in Berlin. During his time in Adlershof, he studied ultrafast reversible structural changes in ferroelectric and ferromagnetic nanolayers as well as the collective solvation dynamics in a molecular crystal. His thesis was evaluated by the Humboldt-University with highest distinction and was awarded the Lise-Meitner-Preis 2009.
With the financial help of a postdoctoral grant of the Swedish Research Council, Clemens now works at the University of Lund and at the synchrotron MAXlab. Here, he continues experimental studies of functional materials with ultrafast X-ray techniques.
The formation and evolution of functional properties of atomic systems, nanostructures or molecules is generally accompanied with structural rearrangements on atomic length and time scales. Time-resolved X-ray diffraction with a temporal resolution of 100 femtoseconds (10-13 s) allows, for the first time, to capture such atomic motions directly to gain a clear picture of the underlying microscopic dynamics.
At the Max-Born-Institute X-ray bursts are produced by interaction of ultra intense and ultra short laser pulses with a thin metal foil, which – similar to a stroboscopic light – freeze the atomic movements in time. This allowed studying the details of the characteristic lattice rearrangements in a ferroelectric nanostructure: triggered by optical excitation the ferroelectric unit cell is compressed along the c-axis within 1500 femtoseconds.
With a small delay of 500 femtoseconds, this leads to a shift of the positively charged central ion, Ti, towards its symmetric position, that is, to an excitation of the ferroelectric “soft mode”, which is directly proportional to the macroscopic polarization, P. For the strongest optical excitation the lattice is compressed by 2% which results in a complete reduction of the macroscopic polarisation within 2000fs.
Contact: Dr. Clemens von Korff Schmising, e-mail
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