Revealing the Photocharge Transfer Mechanism at Manganite-buffered LaAlO3/SrTiO3 Interfaces by Giant Photoresponse

Photoinduced phase transition at complex oxides remains one of very important issues due to the emergent physics and potential applications. In particular, the mechanism of charge transfer at interfaces under irradiation is challenging. Here in, photo-induced properties of manganite-buffered LaAlO3/SrTiO3 interfaces with different thicknesses of buffer layer are systematically investigated. The giant photoresponse is observed and its relative change in the resistance is about 6.24*106 % at T=20 K for the sample with a buffer-layer thickness of 4.8 nm. Moreover, the transition temperature is enhanced with increasing the thickness of buffer layer. More importantly, the dead layer effect at interfaces has been suppressed by using light. All these results are attributed to the charge transfer due to the octahedral tilting at low temperatures and provide a new kind of oxide-based optical devices, such as ultraviolet detectors. This piece of work will pave a path towards two-dimensional-electron-gas based optoe...