Plethora of Many-Body Ground States in Magic Angle Twisted Bilayer Graphene

Seminário Virtual | Monday, May 23, 2022 | 14:00:00
Dmitri Efetov
Twist-angle engineering of 2D materials has led to the recent discoveries of novel many-body ground states in Moiré systems such as correlated insulators, unconventional superconductivity, strange metals, orbital magnetism and topologically nontrivial phases. These systems are clean and tuneable, where all phases can coexist in a single device, which opens up enormous possibilities to address key questions about the nature of correlation induced superconductivity and topology, and allows to create entirely novel quantum phases with enhanced interactions. In this talk we will introduce some of the main concepts underlying these systems, concentrating on magic angle twisted bilayer graphene (MATBG) and show how symmetry-broken states emerge at all integer electron fillings [1]. We further will discuss recent experiments including screened interactions [2], Chern insulators [4], magnetic Josephson junctions [4], quantum criticality [5], re-entrant correlated insulators at high magnetic fields [6] and discuss some of the avenues for novel quantum sensing applications [7].
[1] Nature, 574, 653 (2019).
[2] Nature, 583, 375–378 (2020).
[3] Nature Physics, 17, 710 (2021).
[4] arXiv:2110.01067 (2021).
[5] Nature Physics (2022).
[6] Phys. Rev. Lett. (2022).
[7] arXiv:2111.08735 (2021).
The seminar will be held in a hybrid format. The talk will be transmitted via Zoom, but local participants are also invited to join the IIP community at the auditorium of the Institute.