Anisotropic Interlayer Exciton in GeSe/SnS van der Waals Heterostructure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• Two-dimensional (2D) materials and heterostructures offer novel functionalities.
• Transition metal monochalcogenides (TMCs) possess unique puckered structures.

Purpose of the Study:

• To investigate excitonic bound states in GeSe/SnS van der Waals heterostructures.
• To explore the impact of biaxial strain on electronic and optical properties.

Main Methods:

• GW approximation and Bethe-Salpeter equation (BSE) simulations.
• Computational modeling of van der Waals heterostructures.

Main Results:

• Generation of linearly polarized, anisotropic intra- and interlayer excitonic states.
• Strain-induced dramatic variations in excitonic energies (up to 3%).
• Observation of indirect-to-direct semiconductor transitions and optical spectrum shifts.

Conclusions:

• The puckered structure of TMCs leads to inherent anisotropy in electronic and excitonic properties.
• Biaxial strain effectively controls excitonic energies and optical band gaps by altering dielectric constants and band dispersion.
• Tunable excitonic properties in GeSe/SnS heterostructures hold promise for optoelectronics, quantum computing, and laser applications.