500万彩票

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).