From thermophoresis to novel microscopy techniques.

When rubbing our hands on a cold winter night we are reminded of the intimate connection between friction and heat. Indeed, they both relate to excitation of atomic vibrations (phonons), the first mechanically and the second thermally. A non-equilibrium temperature difference between two points in a lattice gives rise to a flow of phonons from hot to cold. Phonons, although ordinarily only carry crystal momentum at the harmonic level, can carry mechanical momentum too thanks to anharmonic effects. This leads to fascinating phenomena like thermophoresis, where an object is transported by inelastic scattering of a phonon flow due to a thermal gradient. Our group is delving into the fundamental nature of this process and toguether with the group of Dr. Pablo Ares we developing novel microscopy techniques based on this peculiar phenomenon. We can’t reveal too much just yet, so stay tuned!

Sebastian Scherb, Antoine Hinaut*, Rémy Pawlak, J. G. Vilhena*, Yi Liu, Sara Freund, Zhao Liu, Xinliang Feng, Klaus Müllen, Thilo Glatzel, Akimitsu Narita, Ernst Meyer*.
Giant thermal expansion of a two-dimensional supramolecular network triggered by alkyl chain motion
Communications Materials 1, 8 (2020).

Guillermo López-Polín, Maria Ortega, J. G. Vilhena, Irene Alda, J. Gomez-Herrero, Pedro A. Serena, C. Gomez-Navarro and Rubén Pérez.
Tailoring the thermal expansion of graphene via controlled defect creation
Carbon 116, 670 (2017).