Quantum Dots in Transition Metal Dichalcogenides Induced by Atomic-Scale Deformations

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Optics

Background:

• Single-photon emission in 2D materials relies on localized electronic states.
• Transition metal dichalcogenides (TMDs) are promising for optoelectronic applications.

Purpose of the Study:

• To predict the formation of quantum dots in monolayer TMDs.
• To investigate the electronic and optical properties of these defect-induced states.

Main Methods:

• First-principles calculations using density functional theory (DFT).
• Analysis of atomic-scale protrusions, membrane deformation, and resulting electronic band structures.

Main Results:

• Atomic-scale protrusions induce local stretching and curvature, creating localized gap states.
• These states exhibit enhanced outer-surface localization and can mix with chalcogen vacancies and adsorbates.
• Sharp deformations lead to atomic and valley-mixed conduction band minima, enabling quantum light emission.
• Arrayed defects form coupled sub-bands, suggesting superlattice dynamics.

Conclusions:

• Substrate-induced atomic-scale protrusions are a viable route to engineer quantum dots in TMDs.
• Deformation-induced electronic states are crucial for quantum light emission and novel superlattice phenomena.
• Elastic scattering processes play a key role in the observed phenomena.