Light-control of emergent phenomena in van der Waals materials – LIGHT-DRIVE

Understanding and controlling emergent phases in low-dimensional systems is a key challenge in condensed matter physics. Van der Waals (vdW) materials, composed of atomically thin layers, provide an ideal platform for addressing this challenge. Their structure, held together by weak interlayer forces, allows access to unique quantum phenomena such as magnetism, charge density waves (CDWs), and superconductivity in the two-dimensional (2D) limit. The fragile nature of these phases, driven by enhanced fluctuations, offers exceptional tunability by external controls. However, conventional methods like electrical gating or applying pressure face inherent limitations in the speed of phase switching and in the selectivity for specific phases.

LIGHT-DRIVE aims to overcome these limitations using laser-based techniques to induce phase transitions in the least dissipative and fastest ways. This is achieved by selectively driving low-energy excitations like phonons, magnons, and amplitude modes of ordered phases in vdW materials to nonlinear regimes. The project also aims to reveal the intricate cause-and-effect relationships between electrons, spins, and phonons by illuminating their mutual interactions. LIGHT-DRIVE focuses on two key material classes: 2D magnets, where magnetism is stabilized by anisotropy, and layered CDWs featuring competing electronic phases. The core objectives are: i) Can light switch the magnetic states of 2D magnets? ii) Can light effectively initiate dynamical cross-coupling between magnons and phonons at the 2D limit? iii) Can we reshape the free energy landscape through order parameter trajectory steering in materials with multiple competing orders, such as vdW CDWs?

LIGHT-DRIVE seeks to uncover new pathways for light-induced phase transitions. These findings will have implications not only for pushing the boundaries of fundamental physics but also for developing next-generation quantum devices like ultrafast spintronic elements and optoelectronics.