Robust midgap states in band-inverted junctions under electric and magnetic fields

Area of Science:

• Condensed Matter Physics
• Materials Science
• Topological Materials

Background:

• IV-VI semiconductor compounds, such as lead tin telluride, exhibit band-inversion at the L point of the Brillouin zone.
• Band-inversion leads to topologically distinct phases characterized by a change in a topological invariant.
• k·p theory describes band-inversion as a sign change in the fundamental band gap.

Purpose of the Study:

• Investigate midgap interface states in band-inverted junctions under crossed electric and magnetic fields.
• Analyze the robustness of Dirac cone dispersions in these interface states.
• Explore the tunability of Landau levels by electric fields for potential device applications.

Main Methods:

• Utilized a two-band model within the envelope-function approximation.
• Studied band-inverted junctions with the electric field applied along the growth direction.
• Analyzed the behavior of interface electron states in the presence of crossed electric and magnetic fields.

Main Results:

• Predicted and confirmed the appearance of midgap interface states with Dirac cone dispersions in band-inverted junctions.
• Demonstrated the robustness of the Dirac cone dispersion even under strong electric and magnetic fields.
• Showed that Landau levels of electron states can be tailored by the applied electric field.

Conclusions:

• The Dirac cone in band-inverted junctions is a robust feature, persisting under crossed electric and magnetic fields.
• The electric field offers a means to tailor Landau levels, suggesting potential for tunable electronic devices.
• The findings highlight the potential for realizing novel tunable devices based on the unique properties of band-inverted semiconductor junctions.