Welcome to the Dynamics of Correlated Materials group!
XUV generation
High-repetition rate OPCPA
Bond breaking and formation during and ultrafast phase transition
Fermi surface dynamics covering multiple Brillouin zones
Ultrafast dynamics of antiferromagnetic spin arrangements
We are an experimental research group focusing on the investigation of ultrafast processes in strongly correlated materials. Our goal is the understanding of the fundamental interactions at play on the microscopic level in such materials, leading to complex behavior. We develop and employ complementary ultrafast techniques such as time- and angle-resolved photoelectron spectroscopy (trARPES) and time-resolved diffraction techniques to study those elementary interaction processes and couplings across ultrafast phase transitions.
News
Deterministic control of an antiferromagnetic spin arrangement using ultrafast optical excitation
Feb 2020
A central prospect of antiferromagnetic spintronics is to exploit magnetic properties that are unavailable with ferromagnets. However, this poses the challenge of accessing such properties for readout and control. To this end, light-induced manipulation of the transient ground state, e.g. by changing the magnetic anisotropy potential, opens promising pathways towards ultrafast deterministic control of antiferromagnetism. Here, we use this approach to trigger a coherent rotation of the entire long-range antiferromagnetic spin arrangement about a crystalline axis in GdRh2Si2 and demonstrate deterministic control of this rotation upon ultrafast optical excitation. Our observations can be explained by a displacive excitation of the Gd spins′ local anisotropy potential by the optical excitation, allowing for a full description of this transient magnetic anisotropy potential.
New group member: Caio Silva
Jan 2020
We are happy to welcome our new Postdoc Caio Silva to the group!
First time- and momentum-resolved photoemission studies using time-of-flight momentum microscopy at a free-electron laser.
Jan 2020
The free-electron laser FLASH at DESY in Hamburg delivers femtosecond soft-x-ray pulses which allow unique applications in the field of time-resolved photoelectron spectroscopy. We participated in a larger consortium establishing time-resolved momentum microscopy with such 4th generation photon sources. Our paper describing this technical development can be found here: D. Kutnyakhov et al., First time- and momentum-resolved photoemission studies using time-of-flight momentum microscopy at a free-electron laser. Rev. Sci. Instr. 91, 013109 (2020)
New website released!
May 2019
Our website was migrated to the new server and a new design.
Highlight: Ultrafast Dynamics of Atomic Motion Viewed by the Electrons in Solids
Nov 2018
Capturing the motions of atoms in a so-called “molecular movie” is generally thought of as the Holy Grail for understanding chemical transformations or structural phase transitions in solids. However, atomic motion is not the whole story, as the forces driving these motions arise from details of the electronic structure and a gradient across a free energy landscape. Therefore, to obtain a complete picture of the processes driving structural changes, it is necessary to observe the dynamics of the electronic structure and track the temporal evolution of electronic states and their populations. By using femtosecond lasers to perform time- and angle-resolved photoemission spectroscopy, the changes of the electronic structure during the phase transition in indium nanowires on a silicon surface could be closely monitored, allowing a detailed reaction pathway to be extracted. This information combined with simulations of the electronic [more...]
