Quantum critical behaviour in magic-angle twisted bilayer graphene

The flat bands of magic-angle twisted bilayer graphene (MATBG) host strongly-correlated electronic phases such as correlated insulators, superconductors and a strange-metal state. latter state, believed to be key for understanding the properties MATBG, is obscured by various phase transitions thus could not unequivocally differentiated from metal undergoing frequent electron-phonon collisions. Here, we report transport measurements in superconducting MATBG which insulator states are suppressed screening. uninterrupted metallic ground state shows resistivity that linear temperature over three decades spans broad range doping including those where correlation-driven Fermi surface reconstruction occurs. This behavior distinguished Planckian scattering rates magnetoresistivity. In contrast, near charge neutrality or fully-filled band, well devices away magic angle, observe archetypal liquid behavior. Our demonstrate existence quantum critical whose fluctuations dominate throughout continuum doping. Further, transition strange upon suppression order, suggesting relationship between superconductivity MATBG.