Valley splitting of monolayer Hf₃C₂O₂ by the spin-orbit coupling effect: first principles calculations using the...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Mechanics

Background:

• Electrons possess charge, spin, and valley degrees of freedom, crucial for advanced electronics.
• Valleytronics aims to utilize electron valley properties for novel device functionalities.
• Identifying materials with large valley splitting is key to advancing valleytronics.

Purpose of the Study:

• To investigate the electronic and mechanical properties of 1 L Hf₃C₂O₂ using first-principles calculations.
• To assess the potential of 1 L Hf₃C₂O₂ as a two-dimensional material for valleytronic applications.
• To explore the influence of spin-orbit coupling, strain, and doping on its properties.

Main Methods:

• First-principles computations employing the HSE06 functional.
• Inclusion of spin-orbit coupling (SOC) effects.
• Analysis of electronic band structure, Bader charge, elastic constants, phonon spectra, and Berry curvature.
• Investigation of biaxial strain and doping effects on electronic properties.

Main Results:

• 1 L Hf₃C₂O₂ is an indirect bandgap semiconductor (0.952 eV) with significant valley splitting (98.228 meV) between Γ and K conduction bands.
• Hf-O and Hf-C bonds are ionic.
• The material is mechanically and dynamically stable, with non-zero Berry curvature.
• Biaxial strain and doping effectively tune the bandgap and valley splitting.

Conclusions:

• 1 L Hf₃C₂O₂ demonstrates substantial promise as a two-dimensional material for valleytronics.
• Its stability, significant valley splitting, and tunable electronic properties make it a strong candidate for future electronic devices.
• The linear relationship between doping concentration and properties offers precise control for device engineering.