An ideal two-dimensional nodal-ring semimetal in tetragonal borophene oxide

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Two-dimensional (2D) boron materials, or borophenes, typically form triangular lattices with vacancies.
• Borophene stability and structure can change significantly when interacting with substrates or undergoing charge doping.
• Ambient conditions often lead to the oxidation of 2D borophenes, forming more stable oxides.

Purpose of the Study:

• To computationally investigate the potential for creating a stable borophene oxide.
• To characterize the electronic and topological properties of the proposed borophene oxide.
• To explore novel 2D topological materials.

Main Methods:

• First-principles calculations were employed to predict and analyze the material.
• The stability of the proposed borophene oxide was assessed.
• Tight-binding models were developed to understand the electronic structure and nodal ring formation.

Main Results:

• A stable two-dimensional borophene oxide, designated t-B2O, was successfully proposed through the oxidation of unstable T-borophene.
• t-B2O was identified as a topological nodal-ring semimetal, protected by in-plane mirror symmetry.
• The topological nodal ring in t-B2O exhibits minimal energy fluctuation and lacks entanglement with extraneous bands near the Fermi level.

Conclusions:

• The discovery of t-B2O represents a significant advancement in the field of 2D topological materials.
• This work introduces a novel 2D topological nodal-ring semimetal with promising electronic characteristics.
• The methodology employed offers a new perspective for the ongoing search for advanced 2D materials.