Room temperature charge-to-spin conversion from q-2DEG at SrTiO3-based interfaces

Interfacial two-dimensional electron gas (2DEG), especially the SrTiO3-based ones at the unexpected interface of insulators, have emerged to be a promising candidate for efficient charge-spin current interconversion. In this article, to gain insight into the mechanism of the charge-spin current inte...

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Bibliographic Details
Published in:arXiv.org 2022-11
Main Authors: Utkarsh Shashank, Deka, Angshuman, Chen, Ye, Gupta, Surbhi, Medwal, Rohit, Rajdeep Singh Rawat, Asada, Hironori, X Renshaw Wang, Fukuma, Yasuhiro
Format: Article
Language:English
Subjects:
Aluminum oxide
Charge efficiency
Crystal defects
Current modulation
Direct current
Electron gas
Ferromagnetic resonance
Ferromagnetism
Insulators
Oxygen
Room temperature
Spintronics
Strontium titanates
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Summary:Interfacial two-dimensional electron gas (2DEG), especially the SrTiO3-based ones at the unexpected interface of insulators, have emerged to be a promising candidate for efficient charge-spin current interconversion. In this article, to gain insight into the mechanism of the charge-spin current interconversion at the oxide-based 2DEG, we focused on conducting interfaces between insulating SrTiO3 and two types of aluminium-based amorphous insulators, namely SrTiO3/AlN and SrTiO3/Al2O3, and estimated their charge-spin conversion efficiency, {\theta}_cs. The two types of amorphous insulators were selected to explicitly probe the overlooked contribution of oxygen vacancy to the {\theta}_cs. We proposed a mechanism to explain results of spin-torque ferromagnetic resonance (ST-FMR) measurements and developed an analysis protocol to reliably estimate the {\theta}_cs of the oxide based 2DEG. The resultant {\theta}_cs/t, where t is the thickness of the 2DEG, were estimated to be 0.244 nm-1 and 0.101 nm-1 for the SrTiO3/AlN and SrTiO3/Al2O3, respectively, and they are strikingly comparable to their crystalline counterparts. Furthermore, we also observe a large direct current modulation of resonance linewidth in SrTiO3/AlN samples, confirming its high {\theta}_cs and attesting an oxygen-vacancy-enabled charge-spin conversion. Our findings emphasize the defects' contribution to the charge-spin interconversion, especially in the oxide-based low dimensional systems, and provide a way to create and enhance charge-spin interconversion via defect engineering.
ISSN:2331-8422
DOI:10.48550/arxiv.2211.03383