Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32300646.
- Also identified by DOI 10.1126/sciadv.aay0114 and PMC identifier 7148107.
- Licence recorded as CC BY-NC.
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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<sub>3</sub> monolayers by inducing a spin reorientation in (SrRuO<sub>3</sub>)<sub>1</sub>/(SrTiO<sub>3</sub>) <i><sub>N</sub></i> superlattices, in which the magnetic easy axis of Ru spins is transformed from uniaxial 〈001〉 direction (<i>N</i> < 3) to eightfold 〈111〉 directions (<i>N</i> ≥ 3). This eightfold anisotropy enables 71° and 109° spin switching in SrRuO<sub>3</sub> monolayers, analogous to 71° and 109° polarization switching in ferroelectric BiFeO<sub>3</sub>. First-principle calculations reveal that increasing the SrTiO<sub>3</sub> layer thickness induces an emergent correlation-driven orbital ordering, tuning spin-orbit interactions and reorienting the SrRuO<sub>3</sub> 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.