Related Experiment Video
Updated: Aug 22, 2025

Optimized Fabrication Procedure for High-Quality Graphene-based Moiré Superlattice Devices
Published on: July 11, 2025
Pseudospin Paramagnons and the Superconducting Dome in Magic Angle Twisted Bilayer Graphene
Chunli Huang1, Nemin Wei1, Wei Qin1
1Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA.
Abstract:
We present a theory of superconductivity in twisted bilayer graphene in which attraction is generated between electrons on the same honeycomb sublattice when the system is close to a sublattice polarization instability. The resulting Cooper pairs are spin-polarized valley singlets. Because the sublattice polarizability is mainly contributed by interband fluctuations, superconductivity occurs over a wide range of filling fraction. It is suppressed by (i) applying a sublattice polarizing field (generated by an aligned BN substrate) or (ii) changing moiré band filling to favor valley polarization. The enhanced intrasublattice attraction close to sublattice polarization instability is analogous to enhanced like-spin attraction in liquid ^{3}He near the melting curve and the enhanced valley-singlet repulsion close to valley-polarization instabilities is analogous to enhanced spin-singlet repulsion in metals that are close to a ferromagnetic instability. We comment on the relationship between our pseudospin paramagnon model and the rich phenomenology of superconductivity in twisted bilayer and multilayer graphene.
Related Concept Videos
Paramagnetism
Diamagnetism
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets....
Atomic Nuclei: Nuclear Spin State Overview
Atomic Nuclei: Nuclear Magnetic Moment
Potential Due to a Magnetized Object
The vector...
Spin–Spin Coupling Constant: Overview
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...

