Two-Band Nodal Line Structure with Robust Surface States in the Cubic Na₃PdCl₆ Compound

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Physics

Background:

• Topological states have recently expanded to semimetals and metals.
• These materials are characterized by band crossings near the Fermi level.
• Understanding novel topological structures is crucial for advancing quantum materials.

Purpose of the Study:

• To investigate the electronic band structure of cubic Na3PdCl6.
• To identify and characterize any topological nodal line structures.
• To assess the material's stability and potential for applications.

Main Methods:

• First-principles calculations were employed.
• Crystal symmetry analysis was utilized.
• Electronic band structure and surface states were examined.

Main Results:

• A complex nodal line structure with six intersecting butterfly-like nodal lines was uncovered in Na3PdCl6.
• These nodal lines are located on the (110) surface and protected by mirror symmetry M110.
• The topological configuration is robust against Hubbard correction and spin-orbit coupling.

Conclusions:

• Na3PdCl6 exhibits a robust and simple topological nodal line semimetal phase.
• The material demonstrates excellent experimental observability due to its surface states.
• Na3PdCl6 is a promising candidate for fundamental research and technological applications.