PT  - JOURNAL ARTICLE
AU  - Cui, Zhangzhang
AU  - Grutter, Alexander J.
AU  - Zhou, Hua
AU  - Cao, Hui
AU  - Dong, Yongqi
AU  - Gilbert, Dustin A.
AU  - Wang, Jingyuan
AU  - Liu, Yi-Sheng
AU  - Ma, Jiaji
AU  - Hu, Zhenpeng
AU  - Guo, Jinghua
AU  - Xia, Jing
AU  - Kirby, Brian J.
AU  - Shafer, Padraic
AU  - Arenholz, Elke
AU  - Chen, Hanghui
AU  - Zhai, Xiaofang
AU  - Lu, Yalin
TI  - Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer
AID  - 10.1126/sciadv.aay0114
DP  - 2020 Apr 01
TA  - Science Advances
PG  - eaay0114
VI  - 6
IP  - 15
4099  - http://advances.sciencemag.org/content/6/15/eaay0114.short
4100  - http://advances.sciencemag.org/content/6/15/eaay0114.full
SO  - Sci Adv2020 Apr 01; 6
AB  - 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 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 < 3) to eightfold 〈111〉 directions (N ≥ 3). This eightfold anisotropy enables 71° and 109° spin switching in SrRuO3 monolayers, analogous to 71° and 109° 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, multistate device applications.