Gate-Tunable Surface States in Topological Insulator β-Ag₂Te with High Mobility

Area of Science:

• Condensed matter physics
• Materials science

Background:

• Topological insulators are a key focus in condensed matter physics for realizing novel quantum phases.
• Silver chalcogenides, including silver telluride (Ag2Te), are predicted to exhibit topological insulator properties.
• Research on low-dimensional nanostructures of these materials remains limited.

Purpose of the Study:

• To investigate the topological properties of β-silver telluride (Ag2Te) nanostructures.
• To achieve high bulk carrier mobility in Ag2Te nanoplates.
• To explore the tunability of surface and bulk electronic states in Ag2Te.

Main Methods:

• Synthesis of high-quality Ag2Te nanoplates.
• Shubnikov-de Haas oscillations measurements to probe electronic states.
• Electrical transport measurements to determine carrier mobility and surface conductance.

Main Results:

• Achieved a record-high bulk carrier mobility of 298,600 cm^2/(V s) in Ag2Te nanoplates.
• Observed the coexistence of surface and bulk electronic states.
• Demonstrated enhancement of surface conductance contribution up to 87% by tuning surface correlations.

Conclusions:

• Ag2Te nanoplates exhibit exceptional high-mobility properties.
• The material system allows for effective control over surface and bulk state contributions.
• These findings are crucial for advancing high-mobility physics and exploring topological phenomena.