Magneto-Optic Closed-Cycle Cryostat with High-Field Vector-Magnet for Ultrafast Spectroscopy

• Subject Area: Condensed Matter Physics
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543587815

Next-generation concepts and functions for the design of energy technologies are unlocked by discoveries in novel functional energy materials. These break-throughs rely on the investigation of the fundamental mechanisms and structure-property relations of these emerging material systems. A current focus in the AK Deschler are hybrid metal-halide perovskites, which have emerged as promising next-generation polycrystalline semiconductors for optoelectronics, molecular organic semiconductors, and layered nanomaterials. We are interested in the ultrafast dynamics of electronic, structural and magnetic states that are underpinning novel processes and mechanisms in these, and related, emerging materials. For this, we use advanced ultrafast spectroscopic methods, such as transient photoluminescence and transient absorption, spin-sensitive transient Faraday rotation and circularly-polarized spectroscopies, and transient optical holographic microscopy. We currently aim for breakthroughs and fundamental mechanistic insights to advance functionality in hybrid magnetic and organic materials in the areas of: i) Chiral hybrid semiconductors for photonics ii) Magnetic hybrid materials for information technologies iii) Mixed electron-ionic dynamics of energy storage iv) High-resolution advanced ultrafast spectroscopies. We now seek funding for a specialized magneto-optic cryogenic system for ultrafast material characterization. With the proposed system we will gain the ability to investigate ultrafast dynamics in solution-processed semiconductor materials at cryogenic temperatures (below 4K), under high, orientation-controlled magnetic fields (up to 7T), and with microscopic resolution, using our advanced femtosecond spectroscopies. With this special experimental capability, we will gain insights into a little explored regime of excitation and material dynamics in hybrid magnetic semiconductors, from which we expect to discover novel concepts for optoelectronics, information storage and information processing. Details of research directions which will be unlocked by this novel setup, also in collaboration with groups in Heidelberg and nationally, are described in Section 3. The new essential functionality of the system will be the ability to perform our ultrafast optical experiments with femtosecond pulses at cryogenic temperatures, where spin-systems in magnetic materials order, and under strong, directionally-controlled, magnetic fields, which set the magnetic orientation of spin systems with respect to crystal axes and propagation direction of optical pulses. This system will work together with an existing ultrafast laser system to perform advanced optical material investigations with our state-of-the-art spectroscopies. Thus, funding for a multi-component magneto-optic cryostat system is requested, for which the full specifications are described in detail in Section 4.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Magneto-Optischer Kryostat mit Hochfeld-Vektormagnet für Ultraschnelle Spektroskopie
• Instrumentation Group: 8520 Kryostaten, Tauchkühler (bis -100 Grd C)
• Applicant Institution: Ruprecht-Karls-Universität Heidelberg
• Leader: Professor Dr. Felix Deschler