All-angle negative refraction of highly squeezed polaritons in graphene-boron nitride heterostructures

Graphene-boron nitride (BN) heterostructures provide a versatile platform to flexibly tune the sign of the group velocity of the hybrid plasmon-phonon-polaritons, enabling all-angle negative refraction between graphene plasmons, BN's phonon polaritons and their hybrid polaritons.