Joint effect of gate bias and light illumination on metallic LaAlO₃/SrTiO₃ interface

We presented a systemic investigation on the joint effect of gate bias and light illumination on a metallic LaAlO₃/SrTiO₃ interface in the temperature range from 15 K to 300 K. We showed that the photo excitation significantly enhanced the gating effect for the metallic two-dimensional electron gas. However, its effect is strongly temperature dependent; it is strong at low and high temperatures, and weak in the intermediate temperature range. There are evidences that the amplified gating effect stemmed from enhanced carrier depletion while the Hall mobility remains nearly unaffected. Acceleration of the gating process, together with a training effect marked by a strong dependence on gating history of the getting effect, is induced by repeating the electric cycling, indicating atomic reconfiguration due to oxygen migration and the memory of the migration paths.