Hadas Shtrikman

Weizmann Institute of Science, Israel.

Title: Novel (EuIn)As/InAsSb Nanowires Grown by MBE

---

Biography

Abstract

EuIn2As2 is among a vast list of emerging Zentil compounds. It is predicted to be a magnetic topological crystalline insulator consisting of alternating layers of divalent Eu (Eu2+) and In2As2 layers [1,2]. EuIn2As2 bulk single crystals have been grow by a flux method with a by-product which includes trivalent Eu (Eu3+). This work focuses on growth and study of novel, (EuIn)As/InAsSb nanowires produced by molecular beam epitaxy (MBE). In particular, the so called gold assisted vapor liquid solid (VLS) MBE growth of such reclining nanowires. This is a powerful tool for producing various binary and ternary nanowires as well as core/shell structures. These can support hybrid nanoscale devices such as superconductor-semiconductor [3] or ferromagnetic insulator-semiconductor [4] materials with a materials and geometrical variety.

Growth of an (EuIn)As on a wurtzite (WZ) InAs core results in a rough shell in which a unique zinc blende (ZB) like crystal structure is observed. Nevertheless, the so-called stalactites ZB InAs nanowires, which emerge from the merged intersections of two reclining WZ InAs nanowires [5] turn out to have a smooth and uniform surface as seen in Figure 1(a). This inspired us to incorporate Sb into the core nanowires in order to transform the core crystal structure from WZ to ZB and thus assure a smooth coating by the (EuIn)As shell. ZB InAs0.9Sb0.1 nanowires were grown by the gold-assisted vapor–liquid–solid (VLS) MBE, on (001) InAs with and without a WZ InAs stem, [6]. Theoretical modeling using Molecular Dynamics simulations strongly support the substantial difference between the (EuIn)As shell formation on WZ and ZB, where the latter proves to be a significantly better host for the Eu atoms.