Interfacial Bonding and Structure ofBi2Te3Topological Insulator Films on Si(111) Determined by Surface X-Ray Scattering

Abstract

Interfacial topological states are a key element of interest for topological insulator thin films, and their properties can depend sensitively on the atomic bonding configuration. We employ in situ nonresonant and resonant surface x-ray scattering to study the interfacial and internal structure of a prototypical topological film system: Bi2Te3 grown on Si(111). The results reveal a Te-dominated buffer layer, a large interfacial spacing, and a slightly relaxed and partially strained bottom quintuple layer of an otherwise properly stacked bulklike Bi2Te3 film. The presence of the buffer layer indicates a nontrivial process of interface formation and a mechanism for electronic decoupling between the topological film and the Si(111) substrate.

Topological Insulator Film Growth by Molecular Beam Epitaxy: A Review

“…The van der Waals bonding between the Te monolayer used to passivate the silicon substrate and the Bi 2 Te 3 overlayer leads to a fully relaxed film within the first or second monolayer. In Situ x-ray scattering measurements by Liu et al corroborate this finding and show the formation of a Te buffer layer in Te rich growth conditions even when the surface was not purposefully passivated [101]. Growth begins by the formation of many triangular islands which are only weakly bonded to the surface and are thus able to laterally diffuse along the surface.…”

Topological properties of a generalized spin–orbit-coupled Su–Schrieffer–Heeger model

“…The vast majority of attention among researchers has been focused on topological phases of matters [1][2][3][4][5]. Also, a large amount of theoretical and experimental work has been carried out owing to potential applications of topological states as perfect conducting symmetry protected boundary states [6][7][8][9][10] in fault-tolerant quantum computation. There have been several models to realize topological insulators/superconductors in two and three dimensions [1,2].…”

Strain‐engineered atomic‐layer movements and valence‐band maximum shifts in a two‐dimensional single quintuple film of Bi2Te3

“…Very recently, several reports showed that the Raman‐inactive A 2 u mode in bulk Bi 2 Te 3 become Raman active in the films of single and several QLs , which reflects the view that the lattice dynamics in QLs could be drastically different from those in bulk. Moreover, many experiments were performed to realize the properties of topological insulator via the surface engineering of several QLs, such as epitaxial growth of topological insulator film on Si (1,1,1) and the surface relaxation influence on the electronic structure of topological insulators . Theoretical calculations also predicted the electronic structure of single QL Bi 2 Te 3 (BiTe‐1QL), showing an indirect gap semiconductor with localized shallow bands .…”