Enhancement of Rashba spin-orbit coupling by electron confinement at the LaAlO3/SrTiO3 interface

• Published in: Journal of physics. Condensed matter Vol. 32; no. 23; p. 235003
• Main Authors: Liu, Mingrui, Hong, Yanpeng, Xue, Hongxia, Meng, Jianchao, Jiang, Weimin, Zhang, Zhe, Ling, Jingzhuo, Dou, Ruifen, Xiong, Changmin, He, Lin, Nie, Jiacai
• Format: Journal Article
• Language: English
• Published: IOP Publishing 27.05.2020
• Subjects: electron confinement; interface; LaAlO; spatial inversion symmetry breaking; spin-orbit coupling; SrTiO
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/1361-648X/ab7579

Electrical transport property is closely related to the dimensionality of carriers' distribution. In this work, we succeed in tuning the carriers' distribution and the Rashba spin-orbit coupling at LaAlO3/SrTiO3 interface by varying the oxygen pressure (c-PO2) adopted in crystalline LaAlO3 growth. Measurements of the in-plane anisotropic magnetoresistance and the conducting-layer thickness indicate that the carriers' distribution changes from three to two dimensions with c-PO2 increasing, i.e. the electron confinement gets stronger. Importantly, by measuring the low-temperature out-of-plane magnetoresistance and analyzing the weak localization/weak anti-localization, we find that the strength of Rashba spin-orbit coupling can be enhanced by electron confinement. The electron confinement is a manifestation of breaking of spatial inversion symmetry. Therefore, our work reveals the intimate relationship between spatial inversion symmetry breaking and Rashba spin-orbit coupling at the LaAlO3/SrTiO3 interface, and provides a new method to tune the Rashba spin-orbit coupling, which is valuable in the application of oxide-spintronics.