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arXiv · 2608.22989

Discovery of New Zintl Films and Nanowires Grown by Topotaxy Conversion of III-V Semiconductors

Man Suk Song·Lothar Houben·Jean Souza·Edanel Fishbein·Moshe Haim·Ambikesh Gupta·Yufei Zhao·Anna-Eden Kossoy·Binghai Yan·Haim Beidenkopf·Hadas Shtrikman
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Abstract

Zintl phases draw broad interest for their diverse structural, magnetic, thermoelectric, topological and optical properties. Recently, Zintl Eu$_3$In$_2$As$_4$ and Eu$_5$In$_2$As$_6$ nanowires with axion magneto-topology have been synthesized by molecular beam epitaxy via topotactic conversion of InAs wurtzite and zincblende nanowires. Here we extend this methodology, demonstrating that topotaxial mutual-exchange growth applies not only to a broader set of III-V semiconductors beyond InAs but also to three-dimensional substrates whose surfaces are converted into Zintl thin films, as well as to nanowires. We report the growth of two new compounds: Eu$_5$Ga$_2$As$_6$ thin films converted from GaAs substrates, and Eu$_5$Al$_2$As$_6$ thin films from AlAs films. We also convert GaAs nanowires of both wurtzite and zincblende structures into Eu$_5$Ga$_2$As$_6$ nanowires. Though the stoichiometry is the same as in the previously reported Eu$_5$In$_2$As$_6$ case, microscopy and diffraction reveal a single-phase Pnma symmetry group rather than Pbam, highlighting symmetry-guided topotactic pathways to new Zintl frameworks. The compounds host an intricate magnetic phase diagram with three magnetic transitions, including two distinct antiferromagnetic orders and a canted antiferromagnetic phase that evolves into another antiferromagnetic phase under applied field through a spin-flop transition. Ab initio calculations predict that both Zintls are semiconductors with gaps of 0.79 eV in Eu$_5$Ga$_2$As$_6$ and 0.90 eV in Eu$_5$Al$_2$As$_6$. The lower symmetry and increased structural complexity suggest suppressed lattice thermal conductivity, pointing to thermoelectric potential alongside prospects in spintronics and detector technologies. These results give an epitaxy-compatible route for discovering and integrating magnetic Zintl thin films and nanowires directly from relevant III-V semiconductors.

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Man Suk Song, Lothar Houben, Jean Souza, Edanel Fishbein, Moshe Haim, Ambikesh Gupta, Yufei Zhao, Anna-Eden Kossoy, Binghai Yan, Haim Beidenkopf, Hadas Shtrikman. 2026-08-24. Discovery of New Zintl Films and Nanowires Grown by Topotaxy Conversion of III-V Semiconductors. https://arxiv.org/abs/2608.22989

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