Interfacial Electronic Properties at LaAlO3/SrTiO3 Heterointerfaces with Au Nanoclusters Modulated by Visible Light
P. C. Huang1,2*, J. C. Lin3, T. V. Thanh4, T. T. Lin2, B. C. Huang3, Y. P. Chiu1,2,3, J. Y. Lin4, Y. H. Chu3,5
1Department of Physics, National Taiwan Normal University, Taipei, Taiwan
2Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
3Institute of Physics, Academia Sinica, Taipei, Taiwan
4Institute of Physics, National Chiao Tung University, Hsinchu, Taiwan
5Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan
* presenting author:Po-Cheng Huang,
The two-dimensional electron gas has been discovered at the interface between insulating oxides SrTiO3 and LaAlO3. The interfacial metal-insulator transition occurs at the critical thickness of 4 unit cells of the LaAlO3. In the 3 unit cells LaAlO3/ SrTiO3 insulating interface can be modulated by Au nanoclusters on the LaAlO3 surface, the interfacial two-dimensional electron gas presents a giant optical switching effect under green light illumination. In this work, the local density of states has been directly obtained by cross-sectional scanning tunneling microscopy and spectroscopy (XSTM/S) across the LaAlO3/ SrTiO3 hetero-structures. Results have been clearly revealed the built-in electric field of the LaAlO3 and the band bending in the SrTiO3 adjacent to the interface varying with light illumination.

Keywords: cross-sectional scanning tunneling microscopy, SrTiO3, LaAlO3