Spin-polarized tunable photocurrents

Circular dichroism, a distinctively different response to left and right-handed circularly polarized light, is an example of a phenomenon involving light-matter interaction that has been heavily exploited to control valley polarization in two-dimensional materials. In most studies, light-matter interaction enters perturbatively and does not modify the electronic properties. But beyond this weak-coupling regime, Floquet-engineering has shown that we can use light to change the band-structure of a material and even its topology, generating a Hall response.

Light can also be used to generate directed currents even in the absence of an applied bias voltage, a phenomenon called quantum pumping. Here, we go a step further and show how the rich interplay between electron-photon processes, spin-orbit coupling and the symmetry-breaking terms can be harnessed to control spin, charge and valley currents in two-dimensional materials, beyond the weak-coupling regime [1,2]. Notably, we show the possibility of inducing perfectly polarized tunable photocurrents.

[1] M. Berdakin, E. A. Rodríguez-Mena, and L. E. F. Foa Torres, arxiv:2010.11883, https://arxiv.org/abs/2010.11883
[2] Related publications available at http://www.foatorres.com