Topological materials discovery by large-order symmetry indicators

Area of Science:

• Condensed Matter Physics
• Materials Science
• Crystallography

Background:

• Crystalline symmetries are crucial for classifying band structures and understanding topological crystalline phases.
• Topological materials possess unique electronic properties arising from their band structure topology.

Purpose of the Study:

• To efficiently discover novel topological materials using a symmetry indicator method.
• To explore topological materials in specific space groups characterized by large-order symmetry indicators (ℤ8 and ℤ12).
• To identify materials supporting the coexistence of multiple gapless boundary states.

Main Methods:

• Utilized a recently developed method for efficient discovery of topological materials based on symmetry indicators.
• Analyzed five specific space groups for topological properties.
• Identified candidate materials based on large-order symmetry indicators.

Main Results:

• Predicted numerous candidate topological materials, including Pt3Ge, graphite, XPt3 (X=Sn, Pb), Au4Ti, and Ti2Sn.
• Identified AgXF3 (X=Rb, Cs) and AgAsX (X=Sr, Ba) as Dirac semimetals with clean Fermi surfaces.
• Demonstrated that the identified materials support the coexistence of several kinds of gapless boundary states.

Conclusions:

• The discovered materials serve as excellent platforms for investigating the interplay between different types of boundary states.
• The symmetry indicator method is effective for discovering complex topological materials.
• This work expands the landscape of known topological crystalline phases and Dirac semimetals.