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arXiv 2012.07893cond-mat.supr-concond-mat.mtrl-scicond-mat.str-el
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Fe $_{1+y}$ Te $_{1-x}$ Se $_{x}$的磁性、超导和拓扑表面态

Magnetic, superconducting, and topological surface states on Fe$_{1+y}$Te$_{1-x}$Se$_{x}$

Yangmu Li, Nader Zaki, Vasile O. Garlea, Andrei T. Savici, David Fobes, Zhijun Xu, Fernando Camino, Cedomir Petrovic, Genda Gu, Peter D. Johnson, John M. Tranqu… 展开作者

Yangmu Li, Nader Zaki, Vasile O. Garlea, Andrei T. Savici, David Fobes, Zhijun Xu, Fernando Camino, Cedomir Petrovic, Genda Gu, Peter D. Johnson, John M. Tranquada, Igor A. Zaliznyak

摘要:

利用非阿贝尔统计进行无误差量子计算的想法引发了最近关于FeTe $_{0.55}$ Se $_{0.45}$中拓扑表面超导性和马约拉纳零模(MZM)的报道的兴趣。一个相关的难题是,在整个样品表面上观察到的拓扑特征和超导性质并不均匀。这些电子不均匀性的理解和实际控制提出了一个突出的挑战,潜在的应用。在这里,我们结合中子散射,扫描角分辨光电子能谱(ARPES),和微探针组成和电阻率测量,以表征电子状态的Fe $_{1+y}$ Te $_{1-x}$ Se $_{x}$。我们建立了一个相图,其中观察到的超导电性只有在足够低的Fe浓度,与不同的反铁磁相关,而共存的拓扑表面状态只发生在足够高的Te浓度。我们发现FeTe $_{0.55}$ Se $_{0.45}$位于两个相界附近,这解释了超导态和拓扑态的不均匀性。我们的研究结果表明,在实际应用中使用拓扑MZM所需的成分控制。

英文摘要:

The idea of employing non-Abelian statistics for error-free quantum computing ignited interest in recent reports of topological surface superconductivity and Majorana zero modes (MZMs) in FeTe$_{0.55}$Se$_{0.45}$. An associated puzzle is that the topological features and superconducting properties are not observed uniformly across the sample surface. Understanding and practical control of these electronic inhomogeneities present a prominent challenge for potential applications. Here, we combine neutron scattering, scanning angle-resolved photoemission spectroscopy (ARPES), and microprobe composition and resistivity measurements to characterize the electronic state of Fe$_{1+y}$Te$_{1-x}$Se$_{x}$. We establish a phase diagram in which the superconductivity is observed only at sufficiently low Fe concentration, in association with distinct antiferromagnetic correlations, while the coexisting topological surface state occurs only at sufficiently high Te concentration. We find that FeTe$_{0.55}$Se$_{0.45}$ is located very close to both phase boundaries, which explains the inhomogeneity of superconducting and topological states. Our results demonstrate the compositional control required for use of topological MZMs in practical applications.

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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