Electron-photonic topological states on the surface of a bulk semiconductor driven by a high-frequency field

It is shown theoretically that the strong coupling of electrons in a bulk gapless semiconductor (HgTe) to a circularly polarized high-frequency electromagnetic field induces topological states on the surface of the semiconductor. Their branches lie near the center of the Brillouin zone and have the Dirac dispersion. Thus, the light-induced topological phase transition in the semiconductor appears. The structure of the found surface states is studied both analytically and numerically in the broad range of their parameters.