Strong Rashba parameter of two-dimensional electron gas at CaZrO3/SrTiO3 heterointerface

Duhyuk Kwon; Yongsu Kwak; Doopyo Lee; Wonkeun Jo; Byeong-Gwan Cho; Tae-Yeong Koo; Jonghyun Song

doi:10.1038/s41598-023-43247-y

Strong Rashba parameter of two-dimensional electron gas at CaZrO₃/SrTiO₃ heterointerface

Sci Rep. 2023 Sep 23;13(1):15927. doi: 10.1038/s41598-023-43247-y.

Authors

Duhyuk Kwon¹, Yongsu Kwak¹, Doopyo Lee², Wonkeun Jo³, Byeong-Gwan Cho⁴, Tae-Yeong Koo⁴, Jonghyun Song^{5

6}

Affiliations

¹ Department of Physics, Chungnam National University, Daejeon, 34134, Republic of Korea.
² Department of Physics, Pohang University of Science and Technology, Pohang, Gyeongbuk, 37673, Republic of Korea.
³ The Division of Computer Convergence, Chungnam National University, Daejeon, 34134, Republic of Korea.
⁴ Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 37673, Republic of Korea.
⁵ Department of Physics, Chungnam National University, Daejeon, 34134, Republic of Korea. songjonghyun@cnu.ac.kr.
⁶ Institute of Quantum Systems (IQS), Chungnam National University, Daejeon, 34134, Republic of Korea. songjonghyun@cnu.ac.kr.

Abstract

We synthesized a CaZrO₃/SrTiO₃ oxide heterostructure, which can serve as an alternative to LaAlO₃/SrTiO₃, and confirmed the generation of 2-dimensional electron gas (2-DEG) at the heterointerface. We analyzed the electrical-transport properties of the 2-DEG to elucidate its intrinsic characteristics. Based on the magnetic field dependence of resistance at 2 K, which exhibited Weak Anti-localization (WAL) behaviors, the fitted Rashba parameter values were found to be about 12-15 × 10^-12 eV*m. These values are stronger than the previous reported Rashba parameters obtained from the 2-DEGs in other heterostructure systems and several layered 2D materials. The observed strong spin-orbit coupling (SOC) is attributed to the strong internal electric field generated by the lattice mismatch between the CaZrO₃ layer and SrTiO₃ substrate. This pioneering strong SOC of the 2-DEG at the CaZrO₃/SrTiO₃ heterointerface may play a pivotal role in the developing future metal oxide-based quantum nanoelectronics devices.