First-principles calculation of electronic and topological properties of low-dimensional tellurium

TL;DR

This paper uses first-principles calculations to explore the structural, electronic, vibrational, and topological properties of tellurium across various dimensions, revealing diverse topological phases and potential for engineering topological phenomena.

Contribution

It provides a comprehensive first-principles analysis of tellurium's topological phases across different dimensions, including novel findings on 2D topological insulators and 1D helical nanowires.

Findings

Bulk tellurium hosts Weyl nodes and chiral phonons.

Certain 2D tellurene phases are topologically trivial.

Hydrogen-passivated tellurene exhibits a quantum spin Hall phase.

Abstract

We present a comprehensive first-principles investigation of the structural, electronic, vibrational, and topological properties of tellurium across its dimensional hierarchy, including bulk trigonal Te-I, two-dimensional tellurene polymorphs, and one-dimensional helical nanowires. Using density functional theory with full inclusion of spin-orbit coupling, we confirm that bulk Te-I is a narrow-gap semiconductor hosting Weyl nodes arising from broken inversion symmetry and degenerate phonon modes suggestive of chiral phonon behavior. In contrast, two-dimensional alpha and beta-tellurene are found to be topologically trivial, with no spin-orbit-driven band inversion in the occupied manifold. Beyond these established phases, we find that buckled kagome and buckled square tellurene lattices exhibit a nontrivial two-dimensional topology of the occupied electronic bands, indicating incipient quantum spin Hall character in metallic systems. In contrast, one-side hydrogen-passivated hexagonal tellurene realizes a fully gapped quantum spin Hall phase with a robust Z2 = 1 invariant, preserved under applied strain and chemical functionalization. In the one-dimensional limit, helical tellurium nanowires preserve chirality and host edge-localized states accompanied by pronounced anisotropy in carrier effective masses. These results establish tellurium as a highly tunable platform for engineering topological phenomena across dimensionality, bridging three-dimensional Weyl physics, two-dimensional quantum spin Hall and incipient Z2 phases, and one-dimensional helical systems.