Moiré Modulation of Lattice Strains in PdTe2 Quantum Films

Abstract

We Report the Epitaxial Growth of PdTe2 Ultrathin Films on a Topological Insulator Bi2Se3. a Prominent Moiré Pattern Was Observed in Scanning Tunneling Microscope Measurements. the Moiré Periodicity Increases as Film Thickness Decreases, Indicating a Lattice Expansion of Epitaxial PdTe2 Thin Films at Lower Thicknesses. in Addition, Our Simulations based on a Multilayer Relaxation Technique Reveal Uniaxial Lattice Strains at the Edge of PdTe2 Domains, and Anisotropic Strain Distributions throughout the Moiré Supercell with a Net Change in Lattice Strain Up to ∼2.9%. Our Density Functional Theory Calculations Show that This Strain Effect Leads to a Narrowing of the Band Gap at Γ Point Near the Fermi Level. under a Strain of ∼2.8%, the Band Gap at Γ Closes Completely. Further Increasing the Lattice Strain Makes the Band Gap Reopen and the Order of Conduction Band and Valence Bands Inverted in Energy. the Experimental and Theoretical Results Shed Light on a Method for Constructing Quantum Grids of Topological Band Structure under the Modulation of Moiré Potentials.

Department(s)

Physics

Comments

National Science Foundation, Grant DMR 1255607

Keywords and Phrases

heterostructure; moiré pattern; topological insulator; transition metal dichalcogenide

International Standard Serial Number (ISSN)

2053-1583

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2023 IOP Publishing, All rights reserved.

Publication Date

01 Jul 2023

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