Important discovery on the dual character of excitons

The study published in Nature Communications


Excitons are quasiparticles which can transport energy through solid substances. This makes them important for the development of future materials and optoelectronic devices.

A study published in Nature Communications yields crucial new insights on their behaviour: researchers at Politecnico di Milano, in collaboration with the Institute of Photonics and Nanotechnologies IFN-CNR and a theory group from the Tsukuba University (Japan) and the Max Plank Institute for the Structure and Dynamics of matter at Hamburg (Germany), have discovered that an exciton can simultaneously adopt two radically different characters when it is stimulated by light: a solid-like character and an atomic-like character.

The researchers managed to observe the dynamics of excitons in an ultrafast regime, on time scales of the billionth of billionth of second, thanks to the experiments carried out at the Attosecond Research Center within the ERC project AuDACE (Attosecond Dynamics in AdvanCed matErials). With advanced theoretical simulations they have demonstrated the co-existence of the dual characters.

These are significant findings - says lead author Matteo Lucchini from the Politecnico di Milano - because understanding how excitons interact with light on these extreme time scales allows us to envision how to exploit their unique characteristics, fostering the establishment of a new class of electro-optical devices

has explained Matteo Lucchini, researcher at the Department of Physics and lead author of the article.

The study
Lucchini, M., Sato, S.A., Lucarelli, G.D. et al.
Unravelling the intertwined atomic and bulk nature of localised excitons by attosecond spectroscopy
Nat Commun12, 1021 (2021)
The online study