Premium
Length Scale and Dimensionality of Defects in Epitaxial SnTe Topological Crystalline Insulator Films
Author(s) -
Dagdeviren Omur E.,
Zhou Chao,
Zou Ke,
Simon Georg H.,
Albright Stephen D.,
Mandal Subhasish,
MoralesAcosta Mayra D.,
Zhu Xiaodong,
IsmailBeigi Sohrab,
Walker Frederick J.,
Ahn Charles H.,
Schwarz Udo D.,
Altman Eric I.
Publication year - 2017
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201601011
Subject(s) - scanning tunneling microscope , materials science , topological insulator , condensed matter physics , nucleation , molecular beam epitaxy , topological defect , epitaxy , dislocation , crystallographic defect , electron diffraction , atomic units , diffraction , crystallography , optics , nanotechnology , physics , chemistry , layer (electronics) , composite material , quantum mechanics , thermodynamics
Topological crystalline insulators (TCIs) are new materials with metallic surface states protected by crystal symmetry. The properties of molecular beam epitaxy grown SnTe TCI on SrTiO 3 (001) are investigated using scanning tunneling microscopy (STM), noncontact atomic force microscopy, low‐energy and reflection high‐energy electron diffraction, X‐ray diffraction, Auger electron spectroscopy, and density functional theory. Initially, SnTe (111) and (001) surfaces are observed; however, the (001) surface dominates with increasing film thickness. The films grow island‐by‐island with the [011] direction of SnTe (001) islands rotated up to 7.5° from SrTiO 3 [010]. Microscopy reveals that this growth mechanism induces defects on different length scales and dimensions that affect the electronic properties, including point defects (0D); step edges (1D); grain boundaries between islands rotated up to several degrees; edge‐dislocation arrays (2D out‐of‐plane) that serve as periodic nucleation sites for pit growth (2D in‐plane); and screw dislocations (3D). These features cause variations in the surface electronic structure that appear in STM images as standing wave patterns and a nonuniform background superimposed on atomic features. The results indicate that both the growth process and the scanning probe tip can be used to induce symmetry breaking defects that may disrupt the topological states in a controlled way.