Ultrafast Jahn-Teller Photoswitching in Cobalt Single-Ion Magnets

Sophie E. Canton*, Mykola Biednov, Mátyás Pápai, Frederico A. Lima, Tae Kyu Choi, Florian Otte, Yifeng Jiang, Paul Frankenberger, Martin Knoll, Peter Zalden, Wojciech Gawelda, Ahibur Rahaman, Klaus B. Møller, Christopher Milne, David J. Gosztola, Kaibo Zheng, Marius Retegan, Dmitry Khakhulin*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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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.

Original languageEnglish
Article number2206880
JournalAdvanced Science
Issue number21
Number of pages11
Publication statusPublished - 2023


  • Jahn-Teller effect
  • Photoswitching
  • Single-ion-magnets
  • XFEL science


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