Special seminar: Strongly correlated electrons and entropy in twisted bilayer graphene

Wednesday 8 May 2024, 9:30 am

When two sheets of graphene are twisted with respect to each other, strongly correlated electrons emerge within the material. In this talk, I will show evidence that this can lead to Wigner crystallization when the Fermi level is close to the energy gaps in this material.  Furthermore, I will explore how the spin entropy associated with Wigner crystals sheds light on the recently observed "Pomeranchuk effect" in twisted bilayer graphene. This effect causes electrons to "freeze" upon increasing the temperature. Interestingly, this phenomenon opens up avenues for an innovative cooling technique, wherein the electrons themselves serve as a refrigerant. Through simulations, I will illustrate the potential for achieving sub-mK electron temperatures and outline a roadmap for experimental detection of this effect.

dr. Robin Dolleman
Wednesday 8 May 2024, 9:30 am
Dr. Robin Dolleman, University of Aachen, Germany
Huygens building, HG00.622