Fingerprints of native defects in monolayer PbTe

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Understanding nanoscale defect and electron interaction effects is vital for materials development.
• Quantum confinement amplifies these effects in nanostructures, influencing device performance.

Purpose of the Study:

• Investigate optoelectronic properties of pristine and disordered monolayer lead telluride (PbTe).
• Analyze the combined impact of vacancies and electron-electron interactions on electronic and optical characteristics.

Main Methods:

• First-principles calculations using the modified Becke-Johnson potential for pristine electronic structure.
• Generalized Anderson-Hubbard Hamiltonian and many-body typical medium method for defect-influenced electronic structure.
• Bethe-Salpeter equation for absorption spectra, including electron-hole interactions, via valence electron energy-loss spectroscopy (VEELS).

Main Results:

• Observed anomalous spin-orbit coupling dependence in pristine monolayer PbTe.
• Demonstrated vacancy concentration effects: band gap enhancement, resonant shallow impurities, VEELS renormalization, and increased effective plasmon energy.

Conclusions:

• Defects and electron correlations critically tune the optoelectronic properties of monolayer PbTe.
• Vacancy engineering offers a pathway to modify material properties for specific applications.