Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 5: Ultrafast Electron Dynamics at Surfaces and Interfaces I
O 5.1: Vortrag
Montag, 18. März 2024, 10:30–10:45, MA 041
Electronic Structure and Carrier Dynamics of the Bulk Semiconductor Magnet CrSBr — •Lawson Lloyd1, Tommaso Pincelli1,2, Túlio de Castro1, Ferdinand Menzel3, Andreas Stier3, Nathan Wilson3, Martin Wolf1, Laurenz Rettig1, and Ralph Ernstorfer1,2 — 1Fritz Haber Institute, Berlin, Germany — 2TU Berlin, Berlin, Germany — 3TU Munich, Garching, Germany
Van der Waals (vdW) layered magnets have the potential to enable novel optoelectronic and spintronic applications. Among these, CrSBr is a direct band gap semiconductor that hosts interlayer antiferromagnetic order, a highly anisotropic, quasi-1D electronic structure, and strongly bound excitons. However, understanding how the carrier and exciton dynamics couple to the underlying spin order is currently lacking. Here, we employ time- and angle-resolved photoemission spectroscopy to map the temperature-dependent band structure and carrier dynamics in bulk CrSBr. We observe an electronic band splitting that emerges below the magnetic transition temperature, which we interpret as arising from a super-exchange mechanism giving rise to intralayer ferromagnetism. Time-resolved measurements reveal a rapid band renormalization of the lower conduction band that occurs during photoexcitation, pointing towards complex many-body effects governing the excited state dynamics and optical properties. These results provide important experimental observations of the low-temperature electronic band structure and shed further light on the microscopic interactions driving carrier dynamics and spin order in this vdW magnet.