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【物理論壇-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

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:710 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网投正规真人在线信誉平台,

20132015年于阿卜杜拉國王科技大學從事博士后研究,

20152017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:

從事氧化物薄膜网投正规真人在线信誉平台、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网投正规真人在线信誉平台、Advanced Materials、Nano letters 等期刊發表文章二十余篇网投正规真人在线信誉平台,個人被引超過1000次,H因子15。

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).

 

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