Realising time-reversal forbidden photocurrents in non-magnetic materials

Time-reversal symmetry severely constrains the nonlinear optical responses in materials. For example, time-reversal forbidden photocurrents (e.g. linear injection and circular shift photocurrents) have been conventionally thought to only manifest parity violating magnetis such as those of found in antiferromagnets. Here, we propose that by coupling with plasmonic fields, non-vertical interband transitions unblock such time-reversal forbidden photocurrents even in materials that preserve both inversion and time-reversal symmetries. Furthermore, these non-vertical photocurrents exhibit a resonant peak when charge carriers near the Fermi surface are photoexcited. Such Fermi surface resonant effect enables selective sampling of part of the Fermi surface, leading to giant enhancement of optical nonlinearity as well as an ARPES-like photocurrent probe to investigate the quantum geometric properties in non-magnetic and centro-symmetric materials. 

This work was supported by Singapore MOE Academic Research Fund Tier 3 Grant MOE2018-T3-1-002