Topological phase transitions in the photonic spin Hall effect

The recent synthesis of two-dimensional staggered materials opens up burgeoning opportunities to study optical spin-orbit interactions in semiconducting Dirac-like systems. We unveil topological phase transitions in the photonic spin Hall effect in the graphene family materials. It is shown that an external static electric field and a high frequency circularly polarized laser allow for active on-demand manipulation of electromagnetic beam shifts. The spin Hall effect of light presents a rich dependence with radiation degrees of freedom, material properties, and features non-trivial topological properties. We discover that photonic Hall shifts are sensitive to spin and valley properties of the charge carries, providing a unprecedented pathway to investigate spintronics and valleytronics in staggered 2D semiconductors.Comment: Editorially approved for publication in Physical Review Letters 5 pages, 4 figure