Defect charge states in Si doped hexagonal boron-nitride monolayer

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Hexagonal boron-nitride (h-BN) is a promising 2D material.
• Understanding impurity effects is crucial for novel electronic applications.

Purpose of the Study:

• Investigate energetics, electronic, and magnetic properties of silicon (Si) substitutional complexes in h-BN.
• Explore the impact of stoichiometry, clustering, and charge states on Si defects.

Main Methods:

• Ab initio density functional theory (DFT) calculations.
• Analysis of formation energies, electronic structures (partial density of states), and magnetic properties.
• Mulliken population analysis for charge distribution.

Main Results:

• Non-stoichiometric Si substituting boron (SiB) complexes are energetically favorable, half-metallic, and ferromagnetic in the neutral state.
• Magnetic moments and energies increase with Si defect clustering.
• Half-metallicity and magnetism originate from Si 3p impurity states.
• Stoichiometric Si complexes are unfavorable and non-magnetic.
• Formation energies depend on charge state and Fermi level.
• Magnetic properties are tunable via charge state modulation (-2 to +2).
• Half-metallic character is retained in clustered defects upon charging, but lost in isolated defects.

Conclusions:

• Non-stoichiometric SiB complexes in h-BN exhibit tunable half-metallic and ferromagnetic properties.
• Si doping in h-BN offers potential for advanced spintronic devices.
• Charge state and defect clustering are key factors in controlling magnetic behavior.