Elemental Topological Dirac Semimetal α-Sn with High Quantum Mobility

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Alpha-tin (α-Sn) is a promising material for studying topological properties due to its complex topological phase diagram and simple structure.
• Achieving high-quality α-Sn has been a significant challenge, hindering research into its quantum transport and device applications.

Purpose of the Study:

• To achieve high-quality epitaxial growth of α-Sn on InSb (001).
• To investigate the topological properties and quantum transport phenomena in α-Sn.
• To explore potential device applications of α-Sn.

Main Methods:

• Epitaxial growth of α-Sn on InSb (001).
• Measurement of quantum mobilities for surface and bulk states.
• Shubnikov-de Haas oscillations analysis.
• First-principles calculations.

Main Results:

• Achieved unprecedentedly high quantum mobilities for both surface states (30,000 cm² V⁻¹ s⁻¹) and bulk heavy-hole states (1800 cm² V⁻¹ s⁻¹).
• Identified α-Sn on InSb (001) as a topological Dirac semimetal (TDS).
• Demonstrated phase transitions from TDS to a 2D topological insulator and then to a trivial insulator with varying α-Sn thickness.

Conclusions:

• High-quality α-Sn grown on InSb is a robust topological Dirac semimetal.
• The material system exhibits tunable topological phases, making it ideal for fundamental research.
• This work highlights α-Sn as a model system for topological phase studies and a promising candidate for topological electronic devices.