Optically-Controlled Orbitronics on a Triangular Lattice

Abstract

The propagation of electrons in an orbital multiplet dispersing on a lattice can support anomalous transport phenomena deriving from an orbitally-induced Berry curvature. In striking contrast to the related situation in graphene, we find that anomalous transport for an $L=1$ multiplet on the primitive 2D triangular lattice is activated by easily implemented on-site and optically-tunable potentials. We demonstrate this for dynamics in a Bloch band where point degeneracies carrying opposite winding numbers are generically offset in energy, allowing both an anomalous charge Hall conductance with sign selected by off-resonance coupling to circularly-polarized light and a related anomalous orbital Hall conductance activated by layer buckling.

5 + 4 pages, 4 + 1 figures, version accepted to Physical Review Letters