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DOE OSTI · 1631656

Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer

Cui, Zhangzhang·Grutter, Alexander J.·Zhou, Hua·Cao, Hui·Dong, Yongqi·Gilbert, Dustin A.·Wang, Jingyuan·Liu, Yi-Sheng·Ma, Jiaji·Hu, Zhenpeng·Guo, Jinghua·Xia, Jing·Kirby, Brian J.·Shafer, Padraic·Arenholz, Elke·Chen, Hanghui·Zhai, Xiaofang·Lu, Yalin
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Abstract

Engineering magnetic anisotropy in two-dimensional systems has enormous scientific and technological implications. The uniaxial anisotropy universally exhibited by two-dimensional magnets has only two stable spin directions, demanding 180° spin switching between states. We demonstrate a previously unobserved eightfold anisotropy in magnetic SrRuO 3 monolayers by inducing a spin reorientation in (SrRuO 3 ) 1 /(SrTiO 3 ) N superlattices, in which the magnetic easy axis of Ru spins is transformed from uniaxial $\langle 001 \rangle$ direction ( N < 3) to eightfold $\langle 111 \rangle$ directions ( N ≥ 3). This eightfold anisotropy enables 71° and 109° spin switching in SrRuO 3 monolayers, analogous to 71° and 109° polarization switching in ferroelectric BiFeO 3 . First-principle calculations reveal that increasing the SrTiO 3 layer thickness induces an emergent correlation-driven orbital ordering, tuning spin-orbit interactions and reorienting the SrRuO 3 monolayer easy axis. Our work demonstrates that correlation effects can be exploited to substantially change spin-orbit interactions, stabilizing unprecedented properties in two-dimensional magnets and opening rich opportunities for low-power, multistate device applications.

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

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Cui, Zhangzhang, Grutter, Alexander J., Zhou, Hua, Cao, Hui, Dong, Yongqi, Gilbert, Dustin A., Wang, Jingyuan, Liu, Yi-Sheng, Ma, Jiaji, Hu, Zhenpeng, Guo, Jinghua, Xia, Jing, Kirby, Brian J., Shafer, Padraic, Arenholz, Elke, Chen, Hanghui, Zhai, Xiaofang, Lu, Yalin. 2020-04-10. Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer. https://doi.org/10.1126/sciadv.aay0114

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