Roy Anand, Eyal Anna, Majlin Skiff Roni, Barick Barun, Escribano Samuel D, Brontvein Olga, Rechav Katya, Bitton Ora, Ilan Roni, Joselevich Ernesto
Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 76100, Israel.
Physics Department, Technion, Haifa, 32000, Israel.
Adv Mater. 2025 Jul;37(28):e2418279. doi: 10.1002/adma.202418279. Epub 2025 Mar 27.
Nanowires (NWs) of topological materials are emerging as an exciting platform to probe and engineer new quantum phenomena that are hard to access in bulk phase. Their quasi-1D geometry and large surface-to-bulk ratio unlock new expressions of topology and highlight surface states. TaAs, a compensated semimetal, is a topologically rich material harboring nodal-line, weak topological insulator (WTI), C-protected topological crystalline insulator, and Zeeman field-induced Weyl semimetal phases. We report the synthesis of TaAs NWs in situ encapsulated in a dielectric SiO shell, which enable to probe rich magnetotransport phenomena, including metal-to-insulator transition and strong signatures of topologically nontrivial transport at remarkably high temperatures, direction-dependent giant positive, and negative magnetoresistance, and a double pattern of Aharonov-Bohm oscillations, demonstrating coherent surface transport consistent with the two Dirac cones of a WTI surface. The SiO-encapsulated TaAs NWs show room-temperature conductivity up to 15 times higher than bulk TaAs. The coexistence and susceptibility of topological phases to external stimuli have potential applications in spintronics and nanoscale quantum technology.
拓扑材料的纳米线正成为一个令人兴奋的平台，用于探测和设计在体相中难以实现的新量子现象。它们的准一维几何结构和大的表面积与体积比开启了拓扑的新表现形式，并突出了表面态。TaAs是一种补偿半金属，是一种拓扑丰富的材料，包含节线、弱拓扑绝缘体（WTI）、C保护的拓扑晶体绝缘体和塞曼场诱导的外尔半金属相。我们报道了原位封装在介电SiO壳中的TaAs纳米线的合成，这使得能够探测丰富的磁输运现象，包括金属-绝缘体转变以及在非常高的温度下拓扑非平凡输运的强烈特征、方向依赖的巨大正磁阻和负磁阻，以及阿哈罗诺夫-玻姆振荡的双重模式，证明了与WTI表面的两个狄拉克锥一致的相干表面输运。SiO封装的TaAs纳米线在室温下的电导率比块状TaAs高15倍。拓扑相对外界刺激的共存和敏感性在自旋电子学和纳米级量子技术中有潜在应用。
