Magnetic phase transitions for data storage devices

Some materials displays an antiferromagnetic  phase below certain temperature, and a ferromagnetic phase above. Such phase transitions can be exploited for energy efficient magnetic devices. Laser heating can drive FeRh through its antiferromagnetic-to-ferromagnetic phase transition within the first picosecond. By means of accurate modelling and experimental data, the TIMES network will enable a deep understanding on the microscopic mechanism at the origin of the magnetic phase transition, a crucial step for the practical realization of ultrafast storage devices.

Electronic phase transitions for optoelectronic devices

Owing to the coexistence of ferro-, piezo-, and pyro-electricity, and optical non-linearity, the perovskite crystals LiNbO3 and LiTaO3 have seen wide applications in optoelectronics. Recent experimental studies demonstrated the possibility of structural control via ultrashort infrared pulses, leading to transient reversal of ferroelectricity over timescales of a few picoseconds. While quantum nuclear effects and many-body interactions are of pivotal importance to unravel the origin of light-induced non-equilibrium structural dynamics, they are neglected in semi-classical models, and they represent a major challenge for purely ab-initio techniques. The TIMES network will develop novel theoretical and computational methods to explore the influence of electron-phonon interactions, anharmonic and non-adiabatic effects, as well as novel many-body phenomena on the non-equilibrium structural dynamics.

Project: Light-induced phase transitions

The project will explore the tailoring of electron-phonon interaction in solids by means of infrared light pulses, and the light-induced transitions between Fermi liquid and polaronic regime. We will simulate the light control of quasiparticle formation on perovskite compounds with strong coupling to THz radiation.

See related publications on lattice dynamics!

Plasmonic polarons induced by alkali-atom deposition in hafnium disulfide
C. Emeis, SK. Mahatha, S. Rohlf, K. Rossnagel, F. Caruso
Physical Review B 108 (15), 155149 (2023)

Nonequilibrium Lattice Dynamics in Monolayer MoS2
F. Caruso
Journal of Physical Chemistry Letters 12, 1734–1740 (2021)

PI: Fabio Caruso
University of Kiel (Germany)

Project: Light-induced nuclear dynamics

The project will develop a real-space description of light-induced nuclear dynamics with a novel protocol of ab initio (machine-learned) molecular dynamics. The project focusses on 2D materials, oxides, and molecular materials, and we will investigate dynamical nonlinearities in the structural dynamics and material properties.

See RELATED publications on non-equilibrium nuclear dynamics!

On the Role of Nuclear Motion in Singlet Exciton Fission: The Case of Single-Crystal Pentacene
A. Neef, M. Rossi, M. Wolf, R. Ernstorfer, H. Seiler
Physica Status Solidi A221 (1), 2300304 (2024)

Nuclear dynamics of singlet exciton fission in pentacene single crystals
H. Seiler, M. Krynski, D. Zahn, S. Hammer, Y. W. Windsor, T. Vasileiadis, J. Pflaum, R. Ernstorfer, M. Rossi, H. Schwoerer
Science Advances 7 (26), eabg0869 (2021)

PI: Mariana Rossi
MPSD Hamburg (Germany)