Chiral Twist Interface Modulation Enhances Thermoelectric Properties of Tellurium Crystal

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Thermoelectric materials offer a pathway for waste heat energy conversion.
• Manipulating grain boundaries and chiral structures in thermoelectric materials is key to enhancing performance.
• Chiral transport mechanisms in bulk crystals have been largely overlooked.

Purpose of the Study:

• To investigate the impact of interface engineering on thermoelectric properties of Sb-doped Tellurium (Te) crystals.
• To explore the role of embedded Sb2Te3 precipitates in modulating carrier and phonon transport.
• To understand how chiral atomic reorientation influences thermoelectric performance.

Main Methods:

• Growth of Sb-doped Te crystals with embedded Sb2Te3 precipitates.
• Analysis of grain boundary effects and interface structures.
• Measurement of electrical conductivity, thermal conductivity, and power factor.
• Evaluation of the dimensionless figure of merit (zT).

Main Results:

• Achieved low grain boundary scattering and conformationally restructured grain boundaries.
• Observed a twofold increase in power factor compared to polycrystal samples due to high electrical conductivity.
• Demonstrated a significant decrease in lattice thermal conductivity owing to Sb2Te3 precipitates.
• Attained a high dimensionless figure of merit (zT) of 1.1 at 623 K.

Conclusions:

• Interface engineering, specifically the creation of semicoherent interfaces between chiral Te and achiral Sb2Te3, enhances thermoelectric properties.
• Sb-doping and Sb2Te3 precipitates effectively improve electrical transport while scattering phonons.
• Chiral atomic reorientation and interface design are critical for advancing thermoelectric materials for energy conversion.