Ultrafast Jahn‐Teller Photoswitching in Cobalt Single‐Ion Magnets

• Published in: Advanced science Vol. 10; no. 21; pp. e2206880 - n/a
• Main Authors: Canton, Sophie E., Biednov, Mykola, Pápai, Mátyás, Lima, Frederico A., Choi, Tae‐Kyu, Otte, Florian, Jiang, Yifeng, Frankenberger, Paul, Knoll, Martin, Zalden, Peter, Gawelda, Wojciech, Rahaman, Ahibur, Møller, Klaus B., Milne, Christopher, Gosztola, David J., Zheng, Kaibo, Retegan, Marius, Khakhulin, Dmitry
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01.07.2023; John Wiley and Sons Inc; Wiley
• Subjects: Condensed Matter Physics; Den kondenserade materiens fysik; Fysik; Jahn-Teller effect; Ligands; Natural Sciences; Naturvetenskap; photoswitching; Physical Sciences; single-ion-magnets; Spectrum analysis; XFEL science; single-ion-magnets; photoswitching; Jahn-Teller effect; XFEL science
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202206880

Single‐ion magnets (SIMs) constitute the ultimate size limit in the quest for miniaturizing magnetic materials. Several bottlenecks currently hindering breakthroughs in quantum information and communication technologies could be alleviated by new generations of SIMs displaying multifunctionality. Here, ultrafast optical absorption spectroscopy and X‐ray emission spectroscopy are employed to track the photoinduced spin‐state switching of the prototypical complex [Co(terpy)2]2+ (terpy = 2,2′:6′,2″‐terpyridine) in solution phase. The combined measurements and their analysis supported by density functional theory (DFT), time‐dependent‐DFT (TD‐DFT) and multireference quantum chemistry calculations reveal that the complex undergoes a spin‐state transition from a tetragonally elongated doublet state to a tetragonally compressed quartet state on the femtosecond timescale, i.e., it sustains ultrafast Jahn‐Teller (JT) photoswitching between two different spin multiplicities. Adding new Co‐based complexes as possible contenders in the search for JT photoswitching SIMs will greatly widen the possibilities for implementing magnetic multifunctionality and eventually controlling ultrafast magnetization with optical photons. Combined optical and X‐ray spectroscopy experiments complemented by theoretical calculations reveal the photoinduced Jahn‐Teller photoswitching between two spin multiplicities in a Co(II)‐based molecular complex, which occurs on the femtosecond timescale. Unveiling the associated transient magnetic anisotropy will assist the development of such systems into light‐driven multifunctional single‐ion magnets and qubits.