It is shown that chiral plasmons, characterized by a longitudinal magnetic moment accompanying the longitudinal charge plasmon, lead to electromagnetic near-fields that are also chiral. For twisted bilayer graphene, we estimate that the near-field chirality of screened plasmons can be several orders of magnitude larger than that of the related circularly polarized light. The chirality also manifests itself in a deflection angle that is formed between the direction of the plasmon propagation and its Poynting vector. Twisted van der Waals heterostructures might thus provide a novel platform to promote enantiomer-selective physio-chemical processes in chiral molecules without the application of a magnetic field or external nanopatterning that break time-reversal, mirror plane, or inversion symmetry, respectively.
Bibliographical noteFunding Information:
We thank José González and John Schliemann for discussions. This work has been supported by Spain’s MINECO under Grant FIS2017-82260-P, PGC2018-096955-B-C42, and CEX2018-000805-M as well as by the CSIC Research Platform on Quantum Technologies PTI-001. T.S. also acknowledges support from the “Salvador de Madariaga” Programme under Grant PRX19/00024 and from Germany’s Deutsche Forschungsgemeinschaft (DFG) via SFB 1277. T.L. acknowledges support by the National Science Foundation, NSF/EFRI Grant EFRI-1741660.
- light-matter interaction
- twisted bilayer graphene