报告题目 | Itinerant Antiferromagnetism in RuO2 |
报告人 | Prof. Hanno H. Weitering |
报告人单位 | The University of Tennessee, USA |
报告时间 | 2018-06-27 |
报告地点 | 合肥微尺度物质科学国家研究中心九楼会议室(9004) |
主办单位 | 合肥微尺度物质科学国家研究中心、国际功能材料量子设计中心(ICQD) |
报告介绍 | Abstract:
Bulk rutile RuO2 has long been considered a Pauli paramagnet. Here we report that RuO2 exhibits a hitherto undetected lattice distortion below approximately 900 K [1]. The distortion is accompanied by antiferromagnetic order up to at least 300 K with a small room temperature magnetic moment of approximately 0.05μB as evidenced by polarized neutron diffraction. Density functional theory plus U (DFT + U) calculations indicate that antiferromagnetism is favored even for small values of the Hubbard U of the order of 1 eV. The antiferromagnetism may be traced to a Fermi surface instability, lifting the band degeneracy imposed by the rutile crystal field. The combination of high Néel temperature and small itinerant moments make RuO2 unique among ruthenate compounds and among oxide materials in general. In the final part of this talk, I will present some preliminary data of epitaxial RuO2 thin films where the antiferromagnetic correlations are expected to increase.
[1] T. Berlijn et al., PRL 118, 077201 (2017)
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