Structural Design via Pressure Enables zT > 1 for CuInTe₂ Chalcopyrites

Area of Science:

• Materials Science
• Solid-State Physics
• Thermoelectric Energy Conversion

Background:

• Crystalline structures fundamentally dictate material transport properties.
• Optimizing thermoelectric materials often involves structural modifications like doping, alloying, and phase engineering.
• Copper indium telluride (CuInTe2) is a promising thermoelectric material.

Purpose of the Study:

• To design hybrid crystalline architectures in CuInTe2 using high-pressure technology.
• To investigate the impact of these engineered structures on thermoelectric transport properties.
• To enhance the thermoelectric figure of merit (zT) of CuInTe2.

Main Methods:

• Utilized a unique high-pressure technology to introduce hybrid architectures in pristine CuInTe2.
• Introduced localized short-range noncubic lattice distortions alongside a long-range, nearly cubic framework.
• Analyzed the resulting electronic band structure and lattice thermal conductivity.

Main Results:

• Achieved band degeneracy in electronic structures due to long-range ordered frameworks, improving electrical transport.
• Suppressed lattice thermal conductivity via phonon scattering from short-range disordered structures (dense dislocations).
• Obtained a distinguished thermoelectric performance with a figure of merit (zT) of 1.13 at 773 K for CuInTe2 prepared under 3 GPa.

Conclusions:

• Hybrid architectures combining long-range order and short-range disorder effectively enhance thermoelectric properties.
• High-pressure technology is a potent strategy for designing bespoke crystalline structures for thermoelectrics.
• Demonstrated significant potential for CuInTe2 as a high-performance thermoelectric material through structural engineering.