Zero Thermal Expansion in Ta₂Mo₂O₁₁ by Compensation Effects

Area of Science:

• Materials Science
• Solid State Chemistry
• Physics

Background:

• Zero thermal expansion (ZTE) materials are crucial for high-precision engineering but remain scarce.
• Understanding the mechanisms behind ZTE is essential for designing new materials.

Purpose of the Study:

• To report a novel ZTE material, Ta2Mo2O11.
• To elucidate the structural and dynamic mechanisms responsible for the observed ZTE behavior in Ta2Mo2O11.

Main Methods:

• High-resolution synchrotron X-ray diffraction.
• Temperature- and pressure-dependent Raman spectroscopy.
• First-principles calculations.

Main Results:

• A new layered ZTE material, Ta2Mo2O11, was synthesized with near-zero thermal expansion (α = 0.37 × 10⁻⁶ K⁻¹, 200-600 K).
• Analysis revealed a layered structure with expansion along the [001] direction.
• Phonon mode analysis indicated a balance between positive and negative thermal expansion contributions, with in-plane shrinkage and out-of-plane expansion.

Conclusions:

• Ta2Mo2O11 is a promising new material for applications requiring dimensional stability.
• The study provides fundamental insights into the mechanisms governing ZTE in layered structures.