P6: Dynamic band structure control of kagome metals and Mott insulators

• Applicant: Professorin Dr. Isabella Gierz-Pehla
• Subject Area: Experimental Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 531215165

The band structure of a solid is mainly determined by the orbital overlap between neighboring atoms. Therefore, electronic properties are commonly controlled via the chemical composition that determines the relevant structural parameters such as bond angles and lengths. The present project will apply a different approach where control of the effective orbital overlap is achieved by periodic modulation of the solid with strong mid-infrared (MIR) and Terahertz (THz) light fields. The induced band structure changes will be investigated with time- and angle-resolved photoemission spectroscopy (trARPES). We will implement two different driving schemes that either coherently modulate the momentum of the Bloch electrons (Floquet engineering) or the atomic positions (phonon pumping). In this project, we will start by investigating fundamental aspects of the two driving schemes before applying them to kagome metals and Mott insulators. We will address the following key questions: (1) Can we find ways to successfully implement dissipative Floquet engineering? (2) How big are the phonon-pumping-induced band structure changes that can be obtained with experimentally available driving fields? (3) Can we use Floquet engineering and/or phonon pumping to control the electronic properties of kagome metals and Mott insulators?

• DFG Programme: Research Units
• Subproject of: FOR 5750: Optical Control of Quantum Materials (OPTIMAL)