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arXiv 2104.09412cond-mat.str-elcond-mat.mtrl-sci
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压缩反铁磁拓扑绝缘体EuSn2As2的各种磁性

Various magnetism of the compressed antiferromagnetic topological insulator EuSn2As2

Hualei Sun, Cuiqun Chen, Yusheng Hou, Yu Gong, Mengwu Huo, Lisi Li, Jia Yu, Wanping Cai, Naitian Liu, Ruqian Wu, Dao-Xin Yao, Meng Wang

摘要:

我们报告了一个全面的高压研究反铁磁拓扑绝缘体EuSn 2 As 2高达21.1 GPa通过测量同步辐射X射线衍射,电阻,磁阻,霍尔输运结合第一性原理计算。没有检测到明显的结构相变痕迹。由电阻确定的Neel温度在压力下从24 K增加到77 K,这是由于我们的第一性原理计算得到的Eu 2+离子之间的磁交换耦合增强。EuSn_2As_2的负磁电阻效应在高温下持续存在。然而,在10.0GPa以上,观测到的Néel温度的增加明显偏离计算值。此外,磁电阻的大小、霍尔系数和载流子密度在6.9至10.0 GPa之间显示出突变。突变可能源于压力诱导的Eu离子从二价态到二价和三价混合态的价态变化。我们的研究结果提供了洞察EuSn2As2和类似的反铁磁拓扑绝缘体的压力下的磁性的变化。

英文摘要:

We report a comprehensive high-pressure study on the antiferromagnetic topological insulator EuSn2As2 up to 21.1 GPa through measurements of synchrotron x-ray diffraction, electrical resistance, magnetic resistance, and Hall transports combined with first-principles calculations. No evident trace of a structural phase transition is detected. The Neel temperatures determined from resistance are increased from 24 to 77 K under pressure, which is resulted from the enhanced magnetic exchange couplings between Eu2+ ions yielded by our first-principles calculations. The negative magnetoresistance of EuSn2As2 persists to higher temperatures accordantly. However, the enhancement of the observed Néel temperatures deviates from the calculations obviously above 10.0 GPa. In addition, the magnitude of the magnetoresistance, the Hall coefficients, and the charge carrier densities show abrupt changes between 6.9 to 10.0 GPa. The abrupt changes probably originate from a pressure induced valence change of Eu ions from a divalent state to a divalent and trivalent mixed state. Our results provide insights into variation of the magnetism of EuSn2As2 and similar antiferromagnetic topological insulators under pressure.

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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