In‐Plane Nanowire Growth of Topological Crystalline Insulator Pb_{1 − x}Sn_xTe

Abstract

Predicted topological crystalline insulators such as Pb1 − xSnxTe are an interesting candidate for applications in quantum technology, as they can host spin‐polarized surface states. Moreover, in the nanowire geometry, a quasi‐1D system can be realized with potential applications exploiting Majorana fermions. Herein, the selective area growth of Pb1 − xSnxTe islands and nanowires over the full range of x is demonstrated, and their in‐depth growth dynamics and faceting are analyzed. By transmission electron microscopy, the single‐crystalline and defect‐free nature of the grown material and the homogeneous, controllable Pb/Sn ratio in the nanowires is confirmed. With support of phase‐field growth simulations, it is shown that the crystal faceting mainly follows the driving force of surface energy minimization, favoring the lowest energy {200} surfaces. A kinetic enhancement of adatom incorporation on {110} facets is recognized to limit their extension with respect to {200} and {111} facets. After inspecting all possible in‐plane orientations, we identify the 〈110〉 directions as the optimal candidate for the growth of high‐quality and perfectly straight Pb1 − xSnxTe nanowires, enabling the design of complex networks due to their threefold symmetry. This work opens the way to systematic transport investigation of the carrier density in Pb1 − xSnxTe nanowires and can facilitate further optimization of the Pb1 − xSnxTe system.