Title: Anisotropic spin-orbit torque generation in epitaxial SrIrO ₃ by symmetry design

Abstract

Spin-orbit coupling (SOC), the interaction between the electron spin and the orbital angular momentum, can unlock rich phenomena at interfaces, in particular interconverting spin and charge currents. Conventional heavy metals have been extensively explored due to their strong SOC of conduction electrons. However, spin-orbit effects in classes of materials such as epitaxial 5d-electron transition-metal complex oxides, which also host strong SOC, remain largely unreported. In addition to strong SOC, these complex oxides can also provide the additional tuning knob of epitaxy to control the electronic structure and the engineering of spin-to-charge conversion by crystalline symmetry. Here, we demonstrate room-temperature generation of spin-orbit torque on a ferromagnet with extremely high efficiency via the spin-Hall effect in epitaxial metastable perovskite SrIrO₃. We first predict a large intrinsic spin-Hall conductivity in orthorhombic bulk SrIrO₃ arising from the Berry curvature in the electronic band structure. By manipulating the intricate interplay between SOC and crystalline symmetry, we control the spin-Hall torque ratio by engineering the tilt of the corner-sharing oxygen octahedra in perovskite SrIrO₃ through epitaxial strain. This allows the presence of an anisotropic spin-Hall effect due to a characteristic structural anisotropy in SrIrO₃ with orthorhombic symmetry. Our experimental findings demonstrate the heteroepitaxial symmetry designmore » approach to engineer spin-orbit effects. In conclusion, we therefore anticipate that these epitaxial 5d transition-metal oxide thin films can be an ideal building block for low-power spintronics.« less

Authors:

Nan, T. ^[1]; Anderson, T. J. ^[1]; Gibbons, J. ^[2]; Hwang, K. ^[3]; Campbell, N. ^[4]; Zhou, H. ^[5]; Dong, Y. Q. ^[5]; Kim, G. Y. ^[6]; Shao, D. F. ^[7]; Paudel, T. R. ^[7]; Reynolds, N. ^[2]; Wang, X. J.  ^[8];

• Search DOE PAGES for author "Wang, X. J."
• Search DOE PAGES for ORCID "0000-0002-0618-6606"

Sun, N. X. ^[8]; Tsymbal, E. Y. ^[7]; Choi, S. Y. ^[6]; Rzchowski, M. S. ^[4]; Kim, Yong Baek ^[9]; Ralph, D. C. ^[10]; Eom, C. B.  ^[1]

• Search DOE PAGES for author "Eom, C. B."
• Search DOE PAGES for ORCID "0000-0002-8854-1439"

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+ Show Author Affiliations

1. Department of Materials Science and Engineering, University of Wisconsin–Madison, Madison, WI 53706,
2. Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853,
3. Department of Physics and Centre for Quantum Materials, University of Toronto, Toronto, ON M5S 1A7, Canada,
4. Department of Physics, University of Wisconsin–Madison, Madison, WI 53706,
5. Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439,
6. Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Korea,
7. Department of Physics and Astronomy &, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588,
8. Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115,
9. Department of Physics and Centre for Quantum Materials, University of Toronto, Toronto, ON M5S 1A7, Canada,, Canadian Institute for Advanced Research/Quantum Materials Program, Toronto, ON M5G 1Z8, Canada,, School of Physics, Korea Institute for Advanced Study, Seoul 130-722, Korea,
10. Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853,, Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY 14853

Publication Date:

Fri Jul 26 00:00:00 EDT 2019

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1562600

Alternate Identifier(s):

OSTI ID: 1574305

Grant/Contract Number:  

FG02-06ER46327; AC02-06CH11357

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 116 Journal Issue: 33; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

74 ATOMIC AND MOLECULAR PHYSICS; SrIrO3; epitaxial thin films; spin-Hall effect; spin-orbit torque