Work

Strain- and confinement-induced topological phases in noncentrosymmetric wurtzite HgTe

Year: 2026

Type: article

Abstract: While three-dimensional Dirac semimetals have been extensively studied in centrosymmetric materials such as Cd 3 As 2 and Na 3 Bi , the recent colloidal synthesis of wurtzite HgTe (wz-HgTe) opens new opportunities for exploring topological quantum phases in noncentrosymmetric systems. Building on recent evidence that bulk wz-HgTe is a noncentrosymmetric Dirac semimetal, we investigate how strain and quantum confinement reshape its topology. To this end, we combine density-functional theory, semiempirical tight-binding, and k · p approaches. Bulk wz-HgTe hosts two Dirac points along the Γ – A line, i.e., along the c axis, located only 37 meV above the Fermi level, indicating that the Dirac regime should be experimentally accessible by doping or electrostatic gating. We show that biaxial strain drives a sequence of topological phase transitions from a Dirac semimetal to a three-dimensional topological insulator and eventually to a multiband metal. In (0001) thin films, quantum confinement induces oscillatory transitions between trivial and topological insulating phases. We demonstrate that this behavior is governed not only by the underlying s – p band inversion, but also by the crystal-field splitting specific to the wurtzite structure and by the presence of bulk Dirac points. In contrast, ( 1 1 ¯ 00 ) films exhibit a single topological transition and, above a critical thickness, develop surface states forming Fermi-arc-like contours that connect the projections of the Dirac points in the two-dimensional Brillouin zone. In the same weak-confinement regime, semimetallic nanowires oriented along the c axis are predicted to host localized edge states that should be accessible to transport measurements or scanning tunneling spectroscopy. These results establish the topological phase diagram of wz-HgTe beyond the strong-confinement regime explored so far and reveal how crystal symmetry, inversion breaking, strain, and confinement combine to reshape the topology of a Dirac material. More broadly, they identify wurtzite HgTe as a promising platform for engineering topological phases in experimentally relevant nanostructures.

Source: Physical Review Research

DOI: 10.1103/5pj7-34v4

Authors: Antoine Hage, Jing Li, Christophe Delerue