Unveiling Spin Transition at Single-Particle Level in Levitating Spin Crossover Nanoparticles.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41630396.
- Also identified by DOI 10.1021/acsnano.5c18794 and PMC identifier 12918722.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The ability to control and understand phase transitions of individual nanoscale building blocks is key to advancing the next generation of low-power reconfigurable nanophotonic devices. To address this critical challenge, molecular nanoparticles (NPs) exhibiting spin crossover (SCO) phenomenon are trapped by coupling a quadrupole Paul trap to a multispectral polarization-resolved scattering microscope. This contact-free platform simultaneously confines, optically excites, and monitors the spin transition in Fe(II)-triazole NPs in a pressure-tunable environment, eliminating substrate artifacts. Thus, we demonstrate light-driven manipulation of the spin transition in levitating NPs, enabled by laser heating and free of substrate-induced effects. Using the robust spin bistability near room temperature of our SCO system, we quantify reversible optovolumetric changes of up to 10%, revealing precise switching thresholds at the single-particle level. Independent pressure modulation produces a comparable volume increase, confirming mechanical control over the same bistable transition. These results constitute full real-time control and readout of spin states in levitating SCO NPs, with operating conditions compatible with ultralow-power optical switching, data storage, and nanoscale sensing.