具有拓扑表面传导和线性磁电阻的方形网TaSiAs纳米线
Square Net TaSiAs Nanowires with Topological Surface Conduction and Linear Magnetoresistance
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中文总结 AI 辅助
研究合成高质量单晶Si方形网材料TaSiAs纳米线，利用化学气相传输法制备并包裹SiO2，通过原子分辨率分析其结构，观察到丰富电学和磁输运特性，结合计算证明低维方形网拓扑材料独特性质及在多领域的潜在应用。
中文摘要 AI 辅助
方形网拓扑材料因其结构多样性、拓扑保护带和不同电子特性的相互作用而展现出各种有趣特性。但对其低维结构及性质了解甚少。本工作报道了高质量单晶Si方形网材料TaSiAs纳米线的合成与性质。通过化学气相传输制备的纳米线被SiO2薄介电壳化学包裹，具有良好稳定性和原始表面。原子分辨率结构分析揭示了清晰的核壳界面和沿纳米线轴延伸的Si方形网晶格。观察到丰富的电学和磁输运特性，包括室温电阻率比最接近的块状类似物低4至11倍以及非饱和线性磁电阻，揭示了拓扑保护的相干表面输运。第一性原理计算显示了宽范围（4eV）的线性带色散以及由不同对称性保护的狄拉克锥，预测的输运特性与结果一致。这些发现证明了低维方形网拓扑材料的独特性质及其在下一代互连、自旋电子器件和量子计算等方面的潜在应用。
英文摘要
Square-net topological materials exhibit various interesting properties arising from the interplay of their structural diversity, topologically protected bands and different possible electronic features, including intrinsic magnetic ordering and superconductivity. However, little is known about the low-dimensional structures of these materials and their properties. Realization of low-dimensional topological square-net materials has the potential of enabling enhancement of their quantum behavior arising from quasi-compact 1D geometry and high surface-to-volume ratio, and their integration into functional devices. This work reports on the synthesis and properties of high-quality, single-crystal nanowires of Si square-net material TaSiAs. The chemical-vapor-transport produces TaSiAs nanowires that are chemically encapsulated with a thin dielectric shell of SiO2, enabling remarkable ambient stability and a pristine surface, which are critical for observing robust topologically protected surface states. Atomic-resolution structural analysis reveals a sharp core-shell interface, and a Si square-net lattice extending along the nanowire axis. These chemically protected nanowires allowed us to observe rich electrical and magnetotransport features, including 4 to 11 times lower room-temperature resistivity than the closest bulk analogues and non-saturating linear magnetoresistance, revealing topologically protected coherent surface transport. First-principles calculations show a wide-range (4 eV) linear band dispersion, alongside different Dirac cones that are protected by either symmorphic (C4) or non-symmorphic symmetries, predicting transport features consistent with our results. The findings demonstrate the unique properties of low-dimensional square-net topological materials and their potential applications, including next-generation interconnects, spintronic devices and quantum computing.
