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【物理论坛-第66期】Control of real- and reciprocal-space topological properties in SrRuO3 epitaxial ultrathin films

Control of real- and reciprocal-space topological properties in SrRuO3 epitaxial ultrathin films

报告人:王凌飞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.

报告时间:710 下午2:30

报告地点:369彩票204

个人简历:

2013年于中国科学技术大学获凝聚态物理博士学位,

20132015年于阿卜杜拉国王科技大学从事博士后研究,

20152017年于首尔国立大学从事博士后研究,

2018至今于首尔国立大学担任研究助理教授。

研究方向:

从事氧化物薄膜、异质结和原型器件相关工作,2008年至今以第一作者和通讯作者在Nature MaterialsAdvanced MaterialsNano letters 等期刊发表文章二十余篇,个人被引超过1000次,H因子15

报告摘要:

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).