Quantum Non-Reciprocal Responses in Moire Matter

Nonreciprocity lies at the heart of device technology, allowing means to differentiate between forward and backward flows of signals and information. I will describe how the pronounced quantum geometry found in moire quantum matter lead to large non-reciprocal quantum responses that go beyond that of classical means. One striking example is non-reciprocal plasmonics. While traditionally non-reciprocity is traditionally effected using a magnetic field, I will describe how the large quantum metric dipole in twisted bilayer graphene heterostructures enables non-reciprocal bulk plasmons. Strikingly, the strong non-reciprocity persists even for relatively narrow bands underscoring its wavefunction quantum geometric origins. This non-reciprocity of a quantum origin grants a magnetic-field free and passive platform for plasmonic manipulation and opens the door to host of other non-reciprocal responses.<br/><br/>Funding Information: This work was supported by Singapore MOE Academic Research Fund Tier 3 Grant MOE2018-T3-1-002.