Title | Magic-angle semimetals |
Publication Type | Journal Article |
Year of Publication | 2020 |
Authors | Y. Fu, E. J. Konig, J. H. Wilson, Y-Z. Chou, and J. H. Pixley |
Journal | npj Quantum Mater. |
Volume | 5 |
Pagination | 71 |
Date Published | OCT 6 |
Type of Article | Article |
Abstract | Breakthroughs in two-dimensional van der Waals heterostructures have revealed that twisting creates a moire pattern that quenches the kinetic energy of electrons, allowing for exotic many-body states. We show that cold atomic, trapped ion, and metamaterial systems can emulate the effects of a twist in many models from one to three dimensions. Further, we demonstrate at larger angles (and argue at smaller angles) that by considering incommensurate effects, the magic-angle effect becomes a single-particle quantum phase transition (including in a model for twisted bilayer graphene in the chiral limit). We call these models ``magic-angle semimetals{''}. Each contains nodes in the band structure and an incommensurate modulation. At magic-angle criticality, we report a nonanalytic density of states, flat bands, multifractal wave functions that Anderson delocalize in momentum space, and an essentially divergent effective interaction scale. As a particular example, we discuss how to observe this effect in an ultracold Fermi gas. |
DOI | 10.1038/s41535-020-00271-9 |