New topological states in HgTe quantum wells from defect patterning.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Physics

Background:

• The quantum spin Hall (QSH) effect is crucial for spintronic applications.
• Realizing controllable QSH states in two-dimensional (2D) materials remains a challenge.

Purpose of the Study:

• To explore novel methods for achieving the QSH effect in 2D materials.
• To investigate the tunability and localization of topological states.

Main Methods:

• Fabrication of a honeycomb geometry (HG) by etching hexagonal holes in HgTe quantum wells (QWs).
• Theoretical calculations to analyze the electronic band structure and topological properties.

Main Results:

• Honeycomb geometry generates multiple Dirac cones, independent of band inversion.
• Topological states exhibit strong localization at ribbon edges, facilitating manipulation.
• Coexistence of topological states from different mechanisms is possible under specific conditions.

Conclusions:

• The developed HG in HgTe QWs offers a promising platform for realizing and controlling multiple QSH states.
• This work paves the way for designing innovative 2D spintronic materials with tailored topological properties.