Light-induced electronic polarization in antiferromagnetic Cr2O3

An outstanding question is whether external fields can be found that break point group symmetries of only the electronic subsystem. In the current experimental landscape, it is difficult to disentangle the extent to with the electrons or ions respond to static fields like strain, pressure or electric fields. One method to isolate the electronic subsystem is to use a Floquet engineering protocol, where an ultrashort light pulse is shone below the electronic gap. The electrons can then be driven coherently by light's oscillating fields and potentially be decoupled from the lattice. To date, Floquet engineering has been used to manipulate either the rotational symmetry of the spin subsystem or the energy levels of in a solid. In this talk, I will demonstrate that the rotational symmetry of the electronic subsystem can also be manipulated; we show an electronic analogue of the inverse Faraday effect can be realized in Cr2O3. Our work shows how Floquet engineering can be used to manipulate the symmetry of electronic orbitals and break macroscopic point group symmetries.