%0 Journal Article %1 meineke2024ultrafast %A Meineke, Christian %A Schlosser, Jakob %A Zizlsperger, Martin %A Liebich, Marlene %A Nilforoushan, Niloufar %A Mosina, Kseniia %A Terres, Sophia %A Chernikov, Alexey %A Sofer, Zdenek %A Huber, Markus A. %A Florian, Matthias %A Kira, Mackillo %A Dirnberger, Florian %A Huber, Rupert %B Nano Letters %D 2024 %I American Chemical Society %J Nano Lett. %K c %N 14 %P 4101--4107 %R 10.1021/acs.nanolett.3c05010 %T Ultrafast exciton dynamics in the atomically thin van der Waals magnet CrSBr %U https://doi.org/10.1021/acs.nanolett.3c05010 %V 24 %X Among atomically thin semiconductors, CrSBr stands out as both its bulk and monolayer forms host tightly bound, quasi-one-dimensional excitons in a magnetic environment. Despite its pivotal importance for solid-state research, the exciton lifetime has remained unknown. While terahertz polarization probing can directly trace all excitons, independently of interband selection rules, the corresponding large far-field foci substantially exceed the lateral sample dimensions. Here, we combine terahertz polarization spectroscopy with near-field microscopy to reveal a femtosecond decay of paramagnetic excitons in a monolayer of CrSBr, which is 30 times shorter than the bulk lifetime. We unveil low-energy fingerprints of bound and unbound electron–hole pairs in bulk CrSBr and extract the nonequilibrium dielectric function of the monolayer in a model-free manner. Our results demonstrate the first direct access to the ultrafast dielectric response of quasi-one-dimensional excitons in CrSBr, potentially advancing the development of quantum devices based on ultrathin van der Waals magnets.

@article{meineke2024ultrafast, abstract = {Among atomically thin semiconductors, CrSBr stands out as both its bulk and monolayer forms host tightly bound, quasi-one-dimensional excitons in a magnetic environment. Despite its pivotal importance for solid-state research, the exciton lifetime has remained unknown. While terahertz polarization probing can directly trace all excitons, independently of interband selection rules, the corresponding large far-field foci substantially exceed the lateral sample dimensions. Here, we combine terahertz polarization spectroscopy with near-field microscopy to reveal a femtosecond decay of paramagnetic excitons in a monolayer of CrSBr, which is 30 times shorter than the bulk lifetime. We unveil low-energy fingerprints of bound and unbound electron–hole pairs in bulk CrSBr and extract the nonequilibrium dielectric function of the monolayer in a model-free manner. Our results demonstrate the first direct access to the ultrafast dielectric response of quasi-one-dimensional excitons in CrSBr, potentially advancing the development of quantum devices based on ultrathin van der Waals magnets.}, added-at = {2024-04-26T15:22:06.000+0200}, author = {Meineke, Christian and Schlosser, Jakob and Zizlsperger, Martin and Liebich, Marlene and Nilforoushan, Niloufar and Mosina, Kseniia and Terres, Sophia and Chernikov, Alexey and Sofer, Zdenek and Huber, Markus A. and Florian, Matthias and Kira, Mackillo and Dirnberger, Florian and Huber, Rupert}, biburl = {https://www.bibsonomy.org/bibtex/2a2420bb883f488415607ce3c6004b850/ctqmat}, booktitle = {Nano Letters}, comment = {doi: 10.1021/acs.nanolett.3c05010}, day = 20, doi = {10.1021/acs.nanolett.3c05010}, interhash = {b62c140602d6a88e7adc7892534852cb}, intrahash = {a2420bb883f488415607ce3c6004b850}, issn = {15306984}, journal = {Nano Lett.}, keywords = {c}, month = {03}, number = 14, pages = {4101--4107}, publisher = {American Chemical Society}, timestamp = {2024-04-26T15:22:06.000+0200}, title = {Ultrafast exciton dynamics in the atomically thin van der Waals magnet CrSBr}, url = {https://doi.org/10.1021/acs.nanolett.3c05010}, volume = 24, year = 2024 }