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arXiv · 2004.10939

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

Zhangzhang Cui·Alexander J. Grutter·Hua Zhou·Hui Cao·Yongqi Dong·Dustin A. Gilbert·Jingyuan Wang·Yi-Sheng Liu·Jiaji Ma·Zhenpeng Hu·Jinghua Guo·Jing Xia·Brian J. Kirby·Padraic Shafer·Elke Arenholz·Hanghui Chen·Xiaofang Zhai·Yalin Lu
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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 degrees spin switching between states. We demonstrate a novel eightfold anisotropy in magnetic SrRuO3 monolayers by inducing a spin reorientation in (SrRuO3)1/(SrTiO3)N superlattices, in which the magnetic easy axis of Ru spins is transformed from uniaxial <001> direction (N = 1 and 2) to eightfold <111> directions (N = 3, 4 and 5). This eightfold anisotropy enables 71 and 109 degrees spin switching in SrRuO3 monolayers, analogous to 71 and 109 degrees polarization switching in ferroelectric BiFeO3. First-principle calculations reveal that increasing the SrTiO3 layer thickness induces an emergent correlation-driven orbital ordering, tuning spin-orbit interactions and reorienting the SrRuO3 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, multi-state device applications.

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Zhangzhang Cui, Alexander J. Grutter, Hua Zhou, Hui Cao, Yongqi Dong, Dustin A. Gilbert, Jingyuan Wang, Yi-Sheng Liu, Jiaji Ma, Zhenpeng Hu, Jinghua Guo, Jing Xia, Brian J. Kirby, Padraic Shafer, Elke Arenholz, Hanghui Chen, Xiaofang Zhai, Yalin Lu. 2020-04-23. Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer. https://doi.org/10.1126/sciadv.aay0114

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