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.