Gradient engineering enabled thermoelectric performance optimization in LaP/LaAs heterostructures

Area of Science:

• Condensed matter physics
• Materials science
• Solid-state physics

Background:

• Thermoelectric materials performance is enhanced by synergistic band and phonon engineering.
• Gradient engineering offers a novel approach to optimize material properties.

Purpose of the Study:

• Investigate the structure, lattice dynamics, and thermoelectric properties of LaP/LaAs heterostructures.
• Explore the effects of interface modulation on phonon behavior and electronic band structure.
• Evaluate the thermoelectric figure of merit (ZT) in engineered LaP/LaAs heterostructures.

Main Methods:

• First-principles calculations were employed to systematically study the heterostructure.
• Analysis included phonon dispersion curves, band structure, and spin-orbit coupling effects.
• Thermoelectric properties were calculated to determine the figure of merit (ZT).

Main Results:

• Interface modulation altered phonon dispersion, enhancing low-frequency optical and acoustic branch coupling.
• Hybridization of orbitals and spin-orbit coupling induced quasi-reversed band dispersion.
• Optimized carrier transport channels led to improved carrier mobility and conductivity.
• The thermoelectric figure of merit (ZT) reached a maximum of 0.69 along the a-axis and 0.56 along the c-axis at 900 K.

Conclusions:

• Gradient engineering in LaP/LaAs heterostructures significantly improves thermoelectric performance.
• This approach overcomes limitations of traditional thermoelectric materials.
• The study presents a novel strategy for optimizing thermoelectric materials via interface engineering.