Quantum States Induced by Strong Interface Coupling in a 2D VSe₂/Bi₂Se₃ Heterostructure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Vanadium diselenide (VSe2) and Bismuth Selenide (Bi2Se3) are layered materials with unique electronic properties.
• Heterostructures formed by layered materials can exhibit novel quantum phenomena.
• Moiré patterns in heterostructures can lead to emergent electronic states.

Purpose of the Study:

• To fabricate and characterize single-layer (SL) 1T-VSe2/Bi2Se3 heterostructures.
• To investigate the electronic properties and quantum states within these heterostructures.
• To understand the role of strain and charge redistribution in observed quantum states.

Main Methods:

• Molecular Beam Epitaxy (MBE) for heterostructure fabrication.
• Scanning Tunneling Microscopy/Spectroscopy (STM/STS) for surface and electronic state analysis.
• Geometric Phase Analysis (GPA) simulations and Density Functional Theory (DFT) calculations for strain and electronic structure analysis.

Main Results:

• Uniform moiré patterns were successfully fabricated on SL 1T-VSe2/Bi2Se3 heterostructures.
• A robust quantum state near the Fermi energy was observed across the moiré lattice.
• The quantum state exhibited strain dependence, linked to charge redistribution and Se atom orbitals in deformed VSe2.

Conclusions:

• MBE is effective for creating high-quality SL 1T-VSe2/Bi2Se3 heterostructures with moiré superlattices.
• A novel quantum state exists in these heterostructures, modulated by elastic strain.
• The quantum state arises from interfacial charge transfer and strain-induced modifications of VSe2 electronic structure.