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arXiv · 2411.15974

Intertwined topological phases in TaAs2 nanowires with giant magnetoresistance and quantum coherent surface transport

Anand Roy·Anna Eyal·Roni Majlin Skiff·Barun Barick·Samuel D. Escribano·Olga Brontvein·Katya Rechav·Ora Bitton·Roni Ilan·Ernesto Joselevich
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Abstract

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-one-dimensional geometry and large surface-to-bulk ratio unlock new expressions of topology and highlight surface states. TaAs2, a compensated semimetal, is a topologically rich material harboring nodal-line, weak topological insulator (WTI), C2-protected topological crystalline insulator, and Zeeman field-induced Weyl semimetal phases. We report the synthesis of TaAs2 NWs in situ encapsulated in a dielectric SiO2 shell, which enabled us to probe rich magnetotransport phenomena, including metal-to-insulator transition and strong signatures of topologically non-trivial 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 coexistence and susceptibility of topological phases to external stimuli have potential applications in spintronics and nanoscale quantum technology.

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Anand Roy, Anna Eyal, Roni Majlin Skiff, Barun Barick, Samuel D. Escribano, Olga Brontvein, Katya Rechav, Ora Bitton, Roni Ilan, Ernesto Joselevich. 2024-11-24. Intertwined topological phases in TaAs2 nanowires with giant magnetoresistance and quantum coherent surface transport. https://doi.org/10.1002/adma.202418279

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