Terahertz control of surface topology probed with subatomic resolution

Light-induced phase transitions offer a method to dynamically modulate topological states in bulk complex materials. Yet, next-generation devices demand nanoscale architectures with contact resistances near the quantum limit and precise control over local electronic properties. The layered material...

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Bibliographic Details
Published in:arXiv.org 2024-11
Main Authors: Jelic, Vedran, Adams, Stefanie, Maldonado-Lopez, Daniel, Buliyaminu, Ismail A, Hassan, Mohamed, Mendoza-Cortes, Jose L, Cocker, Tyler L
Format: Article
Language:English
Subjects:
Atomic structure
Bulk density
Density functional theory
Dipoles
Fermions
Ferroelectricity
Interlayers
Metastable state
Nanotechnology devices
Phase transitions
Topology
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Summary:Light-induced phase transitions offer a method to dynamically modulate topological states in bulk complex materials. Yet, next-generation devices demand nanoscale architectures with contact resistances near the quantum limit and precise control over local electronic properties. The layered material WTe\(_2\) has gained attention as a likely Weyl semimetal, with topologically protected linear electronic band crossings hosting massless chiral fermions. Here, we demonstrate a topological phase transition facilitated by light-induced shear motion of a single atomic layer at the surface of bulk WTe\(_2\), thereby opening the door to nanoscale device concepts. Ultrafast terahertz fields enhanced at the apex of an atomically sharp tip resonantly couple to the key interlayer shear mode of WTe\(_2\) via a ferroelectric dipole at the interface, inducing a structural phase transition at the surface to a metastable state. Subatomically resolved differential imaging, combined with hybrid-level density functional theory, reveals a shift of 7 \(\pm\) 3 picometres in the top atomic plane. Tunnelling spectroscopy links electronic changes across the phase transition with the electron and hole pockets in the band structure, suggesting a reversible, light-induced annihilation of the topologically-protected Fermi arc surface states in the top atomic layer.
ISSN:2331-8422