Equilibrium Circular Photogalvanic Effect in a Hybrid Superconductor-Semiconductor System

A dc electric current can be induced in a hybrid semiconductor-superconductor system under illumination of it by a circularly polarized light with the frequency below the energy of semiconductor interband transitions. In conditions when the light beam is unable to create real electron-hole excitations, this phenomenon is reminiscent of the Meissner effect in the static magnetic field. Such an effect can be employed in systems combining cavity photons and superconducting quantum circuits.

Figure 1

A sketch of the system. An optically transparent semiconductor film (top) is in a contact with a superconductor (bottom). A thin layer between them depicts a doped quantum well. An incident electromagnetic wave induces in this well an electric current $\mathbf{J}$ perpendicular to the vector $\mathbf{P}\sim \mathbf{E}\times {\mathbf{E}}^{*}$, where $\mathbf{E}$ is the electromagnetic field. The light beam can be also incident from the metal side, if the metal film is thinner than the skin layer.