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Tailoring Kinetics on a Topological Insulator Surface by Defect-Induced Strain: Pb Mobility on Bi2Te3

TitleTailoring Kinetics on a Topological Insulator Surface by Defect-Induced Strain: Pb Mobility on Bi2Te3
Publication TypeJournal Article
Year of Publication2016
AuthorsHuang, WK, Zhang, KW, Yang, CL, Ding, HF, Wan, XG, Li, SC, Evans, JW, Han, Y
JournalNano Letters
Date Published07
Type of ArticleArticle
ISBN Number1530-6984
Accession NumberWOS:000379794200070
Keywords3d, bi2se3, calculations, chemistry, density functional theory, diffusion, film growth, heteroepitaxial film growth, kinetic Monte Carlo simulations, Materials Science, physics, single dirac cone, states, stress, superconductivity, surface adsorption and, Surface strain, Technology - Other Topics, thin-films, topological insulator surface

Heteroepitaxial structures based on Bi2Te3-type topological insulators (TIs) exhibit exotic quantum phenomena. For optimal characterization of these phenomena, it is desirable to control the interface structure during film growth on such TIs. In this process, adatom mobility is a key factor. We demonstrate that Pb mobility on the Bi2Te3(111) surface can be modified by the engineering local strain, epsilon, which is induced around the point-like defects intrinsically forming in the Bi2Te3(111) thin film grown on a Si(111)-7 x 7 substrate. Scanning tunneling microscopy observations of Pb adatom and cluster distributions and first-principles density functional theory (DFT) analyses of the adsorption energy and diffusion barrier E-d of Pb adatom on Bi2Te3(111) surface show a significant influence of epsilon. Surprisingly, E-d reveals a cusp-like dependence on epsilon due to a bifurcation in the position of the stable adsorption site at the critical tensile strain epsilon(c) approximate to 0.8%. This constitutes a very different strain-dependence of diffusivity from all previous studies focusing on conventional metal or semiconductor surfaces. Kinetic Monte Carlo simulations of Pb deposition, diffusion, and irreversible aggregation incorporating the DFT results reveal adatom and cluster distributions compatible with our experimental observations.

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Short TitleNano Lett.
Alternate JournalNano Lett.