# Nematicity Arising from a Chiral Superconducting Ground State in Magic-Angle Twisted Bilayer Graphene under In-Plane Magnetic Fields

(submitted), (2021)

# Nematicity Arising from a Chiral Superconducting Ground State in Magic-Angle Twisted Bilayer Graphene under In-Plane Magnetic Fields

Tao Yu, Dante M. Kennes, Angel Rubio, Michael A. Sentef

Recent measurements of the resistivity in magic-angle twisted bilayer graphene near the superconducting transition temperature show two-fold anisotropy or nematicity when changing the direction of an in-plane magnetic field [Cao \textit{et al.}, arXiv:2004.04148]. This was interpreted as strong evidence for exotic nematic superconductivity instead of the widely proposed chiral superconductivity. Counter-intuitively, we demonstrate that in two-dimensional chiral superconductors the in-plane magnetic field can hybridize the two chiral superconducting order parameters to induce a phase that shows nematicity in the transport response. Its paraconductivity is modulated as cos(2θ B ) , with θ B being the direction of the in-plane magnetic field, consistent with experiment in twisted bilayer graphene. We therefore suggest that, surprisingly, the nematic response reported by Cao \textit{et al.} could provide experimental support for, instead of ruling out, a chiral superconducting state.