Two-dimensional Weyl points and nodal lines in pentagonal materials and their optical response

Area of Science:

• Condensed Matter Physics
• Materials Science
• Theoretical Physics

Background:

• Two-dimensional pentagonal structures, derived from Cairo tiling, form a class of materials with significant physical properties.
• Understanding the electronic and optical characteristics of these materials is crucial for their technological applications.

Purpose of the Study:

• To theoretically investigate the symmetry-based electronic and optical properties of two-dimensional pentagonal materials.
• To classify space groups supporting pentagonal structures in binary and ternary systems.
• To analyze specific material examples for their potential applications.

Main Methods:

• Classification of space groups for pentagonal structures.
• First-principles calculations to determine electronic band structures and local spin textures.
• Analysis of linear and nonlinear optical properties, including shift current.

Main Results:

• Complete classification of space groups for binary and ternary pentagonal systems.
• Identification of Weyl nodes and nodal lines in the electronic band structures of stable materials (PdSeTe, PdSeS, InP5, GeBi2).
• Degeneracies are protected by crystalline and time-reversal symmetries.
• Enhanced shift current observed due to nodal features.

Conclusions:

• Pentagonal structures can host protected topological electronic features like Weyl nodes and nodal lines.
• The investigated materials exhibit promising optical properties, particularly the enhanced shift current.
• These findings highlight the potential of pentagonal materials for future electronic and optoelectronic devices.