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arXiv 2006.00252cond-mat.mtrl-sci
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非磁性带状绝缘体中氧空位诱导的拓扑霍尔效应

Oxygen Vacancy-Induced Topological Hall effect in a Nonmagnetic Band Insulator

Shashank Kumar Ojha, Sanat Kumar Gogoi, Manju Mishra Patidar, Ranjan Kumar Patel, Prithwijit Mandal, Siddharth Kumar, R. Venkatesh, V. Ganesan, Manish Jain, Srimanta Middey

摘要:

近年来,Skyrmions的发现引起了人们对拓扑非平凡自旋织构的极大兴趣。磁矩的非共面特性在电学测量中可以被观察到拓扑霍尔效应。在新材料中并通过新路线实现这种非平凡的自旋纹理是一项持续的努力,因为它们在未来超密度低功耗存储器应用中具有巨大的潜力。本文报道了氧空位(OV)在5 $d^0$体系KTaO $_3$中引起的THE和反常霍尔效应(AHE).在同一温度范围内观察到的弱反局域化行为和THE强烈暗示了自旋轨道耦合(SOC)在THE起源背后的关键作用。从头计算揭示了Ta原子在OV附近的磁矩的形成和传导电子的Rashba型自旋织构。在Rashba SOC存在下,空位周围的局域磁矩可以形成具有非共线自旋织构的束缚磁极化子(BMP),从而产生THE。横向和纵向电阻之间的标度分析建立了斜散射驱动的AHE在这种情况下。我们的研究为通过缺陷工程实现拓扑现象开辟了一条途径。

英文摘要:

The discovery of skyrmions has sparked tremendous interests about topologically nontrivial spin textures in recent times. The signature of noncoplanar nature of magnetic moments can be observed as topological Hall effect (THE) in electrical measurement. Realization of such nontrivial spin textures in new materials and through new routes is an ongoing endeavour due to their huge potential for future ultra-dense low-power memory applications. In this work, we report oxygen vacancy (OV) induced THE and anomalous Hall effect (AHE) in a 5$d^0$ system KTaO$_3$. The observation of weak antilocalization behavior and THE in the same temperature range strongly implies the crucial role of spin-orbit coupling (SOC) behind the origin of THE. Ab initio calculations reveal the formation of the magnetic moment on Ta atoms around the OV and Rashba-type spin texturing of conduction electrons. In the presence of Rashba SOC, the local moments around vacancy can form bound magnetic polarons (BMP) with noncollinear spin texture, resulting THE. Scaling analysis between transverse and longitudinal resistance establishes skew scattering driven AHE in present case. Our study opens a route to realize topological phenomena through defect engineering.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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