Multiferroics: novel magnetoelectric coupling mechanisms, excitations and switching dynamics
The use of ordered (ferroic) materials spans every area of modern technology. Magnetic materials are used for information storage, piezoelectrics are used in sensors and actuators, superconductors are needed to support maglev trains and perform Magnetic Resonance Imaging (MRI). Materials with multiple ferroic orders - multiferroics - combine functionalities of conventional ferroics and promise to break the ground for new devices and functionalities. For example, they could offer electric control of magnetic bits, much sought after due to difficulties with applying magnetic fields in miniature devices and the associated dissipation. We study the complex interactions between bulk orders and between domain walls, and resulting excitations and dynamics.
Ultrafast dynamics of phase transitions (in collaboration with MPI-Hamburg and UCSD)
Recent experiments allowed to track the dynamics of matter on ultrafast timescales, where many important phenomena are taking place. In collaboration with experimental groups, we study rapid phase changes following an intense laser pulse. This work reveals the details of the switching mechanisms in materials with complex orders.
Materials with strong spin-orbit coupling and hidden orders
Electric fields inside materials result in a magnetic field in a co-moving frame of electrons, thus giving rise to the interaction between the orbital and spin degrees of freedom (spin-orbit coupling). These interactions are especially strong in heavy ions due to a large charge of their nuclei. Strong spin-orbit coupling leads to exotic states, such as topologically protected surface states in topological insulators, and to high-multipole orders that are puzzling physicists for many years.