Manipulating Dirac States in BaNiS₂ by Surface Charge Doping.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Dirac semimetals exhibit unique electronic properties due to linear energy-momentum dispersion.
• In BaNiS2, Dirac nodes are unusually located on the Γ-M symmetry line, not at high-symmetry points.
• This unique nodal structure presents opportunities for novel electronic manipulation.

Purpose of the Study:

• To demonstrate the tunability of Dirac bands in BaNiS2 by surface modification.
• To investigate the effect of adsorbed potassium on the electronic structure of BaNiS2.
• To explore a new strategy for engineering Dirac states in materials.

Main Methods:

• First-principles calculations were employed to model the electronic structure.
• The effect of potassium (K) adatoms on BaNiS2 surface was simulated.
• Analysis focused on the charge transfer gap and Dirac band positions.

Main Results:

• Adsorbing potassium onto BaNiS2 successfully shifted the Dirac nodes along the Γ-M line.
• The shift in Dirac nodes was correlated with the electron donation from potassium.
• The charge transfer gap was shown to be a key factor in this tunability.

Conclusions:

• Surface functionalization with potassium provides a viable method to engineer Dirac states in BaNiS2.
• This approach offers a promising route for designing novel electronic properties at surfaces and interfaces.
• The findings pave the way for creating tailored Dirac materials for advanced applications.