Polar vortex hidden in twisted bilayers of paraelectric SrTiO3

Haozhi Sha; Yixuan Zhang; Yunpeng Ma; Wei Li; Wenfeng Yang; Jizhe Cui; Qian Li; Houbing Huang; Rong Yu

doi:10.1038/s41467-024-55328-1

Polar vortex hidden in twisted bilayers of paraelectric SrTiO₃

Nat Commun. 2024 Dec 30;15(1):10915. doi: 10.1038/s41467-024-55328-1.

Authors

Haozhi Sha^#^{1

2

3}, Yixuan Zhang^#⁴, Yunpeng Ma^{1

3}, Wei Li^{1

3}, Wenfeng Yang^{1

2

3}, Jizhe Cui^{1

2

3}, Qian Li^{5

6}, Houbing Huang⁷, Rong Yu^{8

9

10}

Affiliations

¹ School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
² MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing, 100084, China.
³ State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China.
⁴ Advanced Research Institute of Multidisciplinary Science & School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China.
⁵ School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China. [email protected].
⁶ State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China. [email protected].
⁷ Advanced Research Institute of Multidisciplinary Science & School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081, China. [email protected].
⁸ School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China. [email protected].
⁹ MOE Key Laboratory of Advanced Materials, Tsinghua University, Beijing, 100084, China. [email protected].
¹⁰ State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing, 100084, China. [email protected].

^# Contributed equally.

Abstract

Polar topologies, such as vortex and skyrmion, have attracted significant interest due to their unique physical properties and promising applications in high-density memory devices. To date, all known polar vortices are present in or induced by ferroelectric materials. In this study, we find polar vortex arrays in paraelectric SrTiO₃. Using multislice electron ptychography, the evolution of vorticity along the vortex axis is revealed in twisted bilayers of SrTiO₃ with deep-sub-angstrom resolution and one picometer accuracy. The surprising finding of polar vortices in a paraelectric crystal opens up opportunities for polarization physics and corresponding new devices.

Abstract

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