Strongly interacting electrons in solid-state systems often display tendency towards multiple broken symmetries in the ground state. The complex interplay between different order parameters can give rise to a rich phase diagram. Here, we report on the identification of intertwined phases with broken rotational symmetry in magic-angle twisted bilayer graphene (TBG). Using transverse resistance measurements, we find a strongly anisotropic phase located in a 'wedge' above the underdoped region of the superconducting dome. Upon crossing the superconducting dome, a reduction of the critical temperature is observed, similar to the behavior of certain cuprate superconductors. Furthermore, the superconducting state exhibits a anisotropic response to an directional-dependent in-plane magnetic field, revealing a nematic pairing state across the entire superconducting dome. These results indicate that nematic fluctuations might play an important role in the low-temperature phases of magic-angle TBG, and pave the way for using highly-tunable moir\'{e} superlattices to investigate intertwined phases in quantum materials.
@article{arxiv.2004.04148,
title = {Nematicity and Competing Orders in Superconducting Magic-Angle Graphene},
author = {Yuan Cao and Daniel Rodan-Legrain and Jeong Min Park and Fanqi Noah Yuan and Kenji Watanabe and Takashi Taniguchi and Rafael M. Fernandes and Liang Fu and Pablo Jarillo-Herrero},
journal= {arXiv preprint arXiv:2004.04148},
year = {2021}
}