Kinetic pathways towards mass production of single crystalline stanene on topological insulator substrates

Abstract

As a highly appealing new member of the two-dimensional (2D) materials family, stanene was first epitaxially grown on a three-dimensional topological insulator of Bi₂Te₃; yet, to date, a standing challenge is to drastically improve the overall quality of such stanene overlayers for a wide range of potential applications in next-generation quantum devices. Here we use state-of-the-art first-principles approaches to explore the atomistic growth mechanisms of stanene on different Bi₂Te₃(111)-based substrates, with intriguing discoveries. We first show that, when grown on experimentally studied Te-terminated Bi₂Te₃, stanene would follow an unusual partial-layer-by-partial-layer growth mode, characterized by short-range repulsive pairwise interactions of the Sn adatoms; the resultant stanene overlayer is destined to contain undesirable grain boundaries. More importantly, we find that stanene growth on Bi₂Te₃(111) pre-covered with a Bi bilayer follows a highly desirable nucleation-and-growth mechanism, strongly favoring single crystalline stanene. We further show that both systems exhibit pronounced Rashba spin–orbit couplings, while the latter system also provides new opportunities for the potential realization of topological superconductivity in 2D heterostructures. The novel kinetic pathways revealed here will be instrumental in achieving the mass production of high-quality stanene with emergent physical properties of technological significance.