Synthesis of High-Entropy Gradient Crystals via the Soret Effect during Bridgman Growth

Area of Science:

• Materials Science
• Solid State Physics
• Crystallography

Background:

• Functionally gradient materials offer tunable properties by varying composition or structure.
• High-entropy crystals, with multiple elements, are promising for gradient material development.
• Synthesizing high-entropy gradient crystals is challenging due to inherent disorder.

Purpose of the Study:

• To establish a general approach for synthesizing high-entropy gradient crystals.
• To demonstrate the feasibility of using the Soret effect in Bridgman growth for this purpose.
• To explore the thermoelectric properties of the synthesized materials.

Main Methods:

• Utilized the Soret effect within the Bridgman crystal growth method.
• Employed a polycrystalline AgSbPbSnGeTe5 precursor.
• Applied macroscopic and microscopic temperature gradients during crystal growth.

Main Results:

• Successfully synthesized the first high-entropy gradient crystals using the Soret effect.
• Achieved dense, intact millimeter-sized single crystals.
• Demonstrated a high thermoelectric figure of merit (ZT) of ~1.44 at 673 K.

Conclusions:

• The Soret effect in Bridgman growth provides a general paradigm for creating high-entropy gradient crystals.
• This method facilitates the synthesis of large-sized high-entropy single crystals.
• The synthesized materials show significant potential for thermoelectric applications.