Univ. Paris-Saclay

Service de Physique de l'Etat Condensé

Fermi liquid and strange-metal behaviors in twisted bilayer graphene.
Alexandre Jaoui
LMU Munich
Jeudi 29/06/2023, 15:00-16:01
Amphi. Bloch, Bât. 774, Orme des Merisiers, CEA-Saclay

Moiré materials, designed by stacking 2D materials with a controlled misalignment, were recently shown to host a panel of many-body ground states. As an example, twisted bilayer graphene (TBG), can be tuned into a superconductor [1], correlated insulator [2], magnet or topologically nontrivial phase [3] by in-situ electrostatic gating. In this seminar, we will show that the metallic regime in the direct vicinity of these correlated phases displays a non-conventional ‘strange-metal’ behavior [4]. This state echoes that of other families of strongly correlated materials,
such as the cuprates, and has been escaping theoretical understanding for several decades. On the contrary, away from these correlated states, TBG reverts to the canonical Fermi liquid behavior.
These observations shed light on the underlying microscopic mechanisms that drive the metallic ground state, and they establish moiré materials as highly tunable platforms for investigating strange-metallicity in superconductors.

[1] Y. Cao, et al., Nature 556, 43-50 (2018).
[2] Y. Cao et al., Nature 556, 80-84 (2018).
[3] X. Lu et al., Nature 574, 653-657 (2019).
[4] A. Jaoui et al., Nature Physics 18, 633-638 (2022).

Contact : Marceau HENOT


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