Team finds Wigner crystal -- Mott insulator in 'magic-angle' graphene

Phys.org (Sept. 24) -- Recently, a team of scientists led by Pablo Jarillo-Herrero at the Massachusetts Institute of Technology (MIT) created a huge stir in the field of condensed matter physics when they showed that two sheets of graphene twisted at specific angles—dubbed “magic-angle” graphene—display two emergent phases of matter not observed in single sheets of graphene. Researchers at the University of Illinois at Urbana-Champaign have recently shown that the insulating behavior reported by the MIT team has been misattributed. Professor Philip Phillips, a noted expert in the physics of Mott insulators, says a careful review of the MIT experimental data by his team revealed that the insulating behavior of the “magic-angle” graphene is not Mott insulation, but something even more profound—a Wigner crystal. Also: Science Daily (Sept. 24).