Nematicity and competing orders in superconducting magic-angle graphene

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 its crossing with the superconducting dome, a reduction of the critical temperature is observed. Furthermore, the superconducting state exhibits an anisotropic response to a direction-dependent in-plane magnetic field, revealing nematic ordering 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.

Source: ScienceNOW - April 15, 2021 Category: Science Authors: Cao, Y., Rodan-Legrain, D., Park, J. M., Yuan, N. F. Q., Watanabe, K., Taniguchi, T., Fernandes, R. M., Fu, L., Jarillo-Herrero, P. Tags: Materials Science, Physics r-articles Source Type: news