Interplay between Structural, Electronic, and Topological Properties in Low-Dimensional Tellurium

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Topological materials exhibit unique electronic properties governed by their band structure topology.
• Tellurium's dimensional hierarchy offers a platform for exploring diverse topological phases.
• Understanding these properties is crucial for developing novel electronic and spintronic devices.

Purpose of the Study:

• To comprehensively investigate the structural, electronic, vibrational, and topological properties of tellurium across its dimensional hierarchy.
• To explore the potential of tellurium-based materials for hosting topological phenomena.
• To identify new topological phases in tellurium polymorphs and nanostructures.

Main Methods:

• First-principles calculations using density functional theory (DFT).
• Inclusion of spin-orbit coupling (SOC) to accurately capture relativistic effects.
• Analysis of electronic band structures, phonon modes, and topological invariants (Z2).

Main Results:

• Bulk trigonal tellurium (Te-I) exhibits Weyl nodes and chiral phonon behavior.
• Two-dimensional (2D) α- and β-tellurene are topologically trivial.
• Buckled kagome and square tellurene lattices show nontrivial 2D Z2 topology, indicating incipient quantum spin Hall (QSH) character.
• Hexagonal tellurene realizes a robust, gapped QSH phase with a Z2 = 1 invariant, stable under strain and functionalization.
• One-dimensional (1D) helical tellurium nanowires host edge states with anisotropic effective masses.

Conclusions:

• Tellurium serves as a versatile platform for engineering topological phenomena across 3D, 2D, and 1D systems.
• The study bridges 3D Weyl physics, 2D QSH and incipient Z2 phases, and 1D helical systems.
• These findings pave the way for novel topological materials and devices.