Physics Colloquium
Probing flat-bands in twisted bilayer graphene
Twist-angle engineering of two-dimensional materials has led to the recent discoveries of novel many-body ground states in moiré systems such as correlated insulators, unconventional superconductivity, strange metals, orbital magnetism, and topologically nontrivial phases. These systems are exceptionally clean and tunable, allowing correlated electronic phases to coexist within a single device and enabling key questions about the nature of correlation-induced superconductivity and topology to be addressed, as well as the creation of entirely novel quantum phases with enhanced interaction energies and temperatures. In this talk we introduce some of the main concepts underlying these systems, concentrating on magic-angle twisted bilayer graphene (MATBG) and show how we can engineer strongly interacting, topological and superconducting states. We further discuss recent efforts to explore the vast library of novel bilayer moiré materials using a high-throughput quantum twisted microscope (QTM) technique, enabling the search for exotic ground states with ever higher interaction energy scales and temperatures. Finally, we present recent quantum technology developments enabled by ultra-low carrier-density superconducting states in MATBG, including demonstrations of highly tunable single-photon detectors.