Spin magnetometry as a probe of stripe superconductivity in twisted bilayer graphene

TL;DR

This paper proposes using spin magnetometry to explore stripe superconductivity in twisted bilayer graphene, revealing fractionalized quantum states and providing insights into high-temperature superconductivity mechanisms.

Contribution

It demonstrates that small angle twisted bilayer graphene can emulate stripe-ordered phases and fractionalized quantum states, offering a new platform for studying high-$T_c$ superconductivity.

Findings

Fractionalization of spin and valley quantum numbers in TBG stripes

Signatures in tunneling density of states and magnetic noise spectrum

Determination of superconducting transition temperature from coupling analysis

Abstract

The discovery of alternating superconducting and insulating ground-states in magic angle graphene has suggested an intriguing analogy with cuprate high-$T_c$ materials. Here we argue that the network states of small angle twisted bilayer graphene (TBG) afford a further perspective on the cuprates by emulating their stripe-ordered phases, as in La$_{1.875}$Ba$_{0.125}$CuO$_4$. We show that the spin and valley quantum numbers of stripes in TBG graphene fractionalize, developing characteristic signatures in the tunneling density of states and the magnetic noise spectrum of impurity spins. By examining the coupling between the charge rivers we determine the superconducting transition temperature. Our study suggests that magic angle graphene can be used for a controlled emulation of stripe superconductivity and quantum sensing experiments of emergent anyonic excitations.