Control of real- and reciprocal-space topological properties in SrRuO3 epitaxial ultrathin films
報告人:王凌飛1,2*
1 Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, Republic of Korea.
2 Department of Physics and Astronomy, Seoul National University, Seoul, Republic of Korea.
報告時間:7月10日 下午2:30
報告地點:物理學院204

個人簡歷:
2013年于中國科學技術大學獲凝聚態物理博士學位,
2013至2015年于阿卜杜拉國王科技大學從事博士后研究,
2015至2017年于首爾國立大學從事博士后研究,
2018至今于首爾國立大學擔任研究助理教授。
研究方向:
從事氧化物薄膜500万彩票、異質結和原型器件相關工作,2008年至今以第一作者和通訊作者在Nature Materials、Advanced Materials、Nano letters 等期刊發表文章二十余篇,個人被引超過1000次,H因子15500万彩票。
報告摘要:
Perovskite-structured SrRuO3 is a prototypical ferromagnetic metal with a Curie temperature of ~ 160 K.[1] A fine balance between the electron-electron correlation and spin-orbit coupling in SrRuO3 gives rise to a variety of exotic physical properties, including itinerant ferromagnetism, non-Fermi liquid electrical transport, magnetic monopoles in momentum space, and tunable magnetic skyrmions.[1-3]
Here, we will show our recent results about tunable real-space and reciprocal-space topological properties in SrRuO3 ultrathin films. In the first part, we will report the discovery of ferroelectrically tunable skyrmions in ultrathin BaTiO3/SrRuO3 bilayer heterostructures. In this epitaxial system, ferroelectric proximity effect at the BaTiO3/SrRuO3 heterointerface can trigger a sizable Dzyaloshinskii-Moriya interaction, thus stabilizing magnetic skyrmions with a diameter of ~100 nm. Thanks to the strong coupling between ferroelectric distortion and Dzyaloshinskii-Moriya interaction, we can achieve local, switchable, and nonvolatile control of both skyrmion density and thermodynamic stability.[4] In the second part, we will focus on the highly tunable anomalous Hall effect in SrRuO3 single layers. We found the anomalous Hall coefficient exhibit a clear sign reversal as the SrRuO3 film thickness decreases to 4 unit-cells. This behavior is dominated by the non-trivial topology and large Berry curvature at the avoided crossing points in SrRuO3 band structure. By harnessing the step-flow growth mode and artificially inducing a thickness non-uniformity, we can further modulate such a reciprocal-space topology-dominated magnetotransport. At last, we will propose several experimental methods for identifying the differences between the skyrmion-induced topological Hall effect and thickness inhomogeneity induced anomalous Hall effect.
[1] Koster, G. et al. Review of Modern Physics 84, 253–298 (2012).
[2] Fang, Z. et al. Science 302, 92 (2003).
[3] Ohuchi, Y. et al. Nature Communications 9, 213 (2018).
[4] Wang, L. et al. Nature Materials 17, 1087 (2018).