Fully Optical Modulation of the Two-Dimensional Electron Gas at the γ-Al 2 O 3 /SrTiO 3 Interface

• Published in: The journal of physical chemistry letters Vol. 13; no. 13; pp. 2976 - 2985
• Main Authors: Niu, Wei, Fang, Yue-Wen, Liu, Ruxin, Wu, Zhenqi, Chen, Yongda, Gan, Yulin, Zhang, Xiaoqian, Zhu, Chunhui, Wang, Lixia, Xu, Yongbing, Pu, Yong, Chen, Yunzhong, Wang, Xuefeng
• Format: Journal Article
• Language: English
• Published: United States 07-04-2022
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.2c00384

Two-dimensional electron gas (2DEG) formed at the heterointerface between two oxide insulators hosts plenty of emergent phenomena and provides new opportunities for electronics and photoelectronics. However, despite being long sought after, on-demand properties controlled through a fully optical illumination remain far from being explored. Herein, a giant tunability of the 2DEG at the interface of γ-Al
O
/SrTiO
through a fully optical gating is discovered. Specifically, photon-generated carriers lead to a delicate tunability of the carrier density and the underlying electronic structure, which is accompanied by the remarkable Lifshitz transition. Moreover, the 2DEG can be optically tuned to possess a maximum Rashba spin-orbit coupling, particularly at the crossing region of the sub-bands with different symmetries. First-principles calculations essentially well explain the optical modulation of γ-Al
O
/SrTiO
. Our fully optical gating opens a new pathway for manipulating emergent properties of the 2DEGs and is promising for on-demand photoelectric devices.