Topotaxial Mutual-Exchange Growth of Magnetic Zintl EuInAs Nanowires with Axion Insulator Classification
arXiv:2406.18956 · doi:10.1038/s41565-024-01762-7
Abstract
Nanomaterials bring to expression unique electronic properties that promote advanced functionality and technologies. Albeit, nanoscale growth presents paramount challenges for synthesis limiting the diversity in structures and compositions. Here, we demonstrate solid-state topotactic exchange that converts Wurtzite InAs nanowires into Zintl phase EuInAs nanowires. In situ evaporation of Eu and As over InAs nanowire cores in molecular beam epitaxy results in mutual exchange of Eu from the shell and In from the core. A continuous EuInAs shell thereby grows that gradually consumes the InAs core and converts it into a single phase EuInAs nanowire. Topotaxy, which facilitates the mutual exchange, is supported by the substructure of the As matrix which is similar across the Wurtzite InAs and Zintl EuInAs. We provide initial evidence of an antiferromagnetic transition at T 6.5 K in the Zintl phase EuInAs nanowires. Ab initio calculation confirms the antiferromagnetic state and classifies EuInAs as a axion insulator hosting both chiral hinge modes and unpinned Dirac surface states. The topotactic mutual-exchange growth of Zintl EuInAs nanowires thus enables the exploration of intricate magneto-topological states of nanomaterials. Moreover, it may open the path for topotactic mutual-exchange synthesis of nanowires made of other exotic compounds.
45 pages, 23 figures