Negative Thermal Expansion (NTE) Materials Database

A curated platform for NTE materials data and a physically transparent descriptor framework. We combine material records with the shear-bond ratio classifier ξ = G/Ẽ to help identify whether a material tends toward NTE or PTE behavior.

Why NTE Matters

Most materials expand when heated (positive thermal expansion), while NTE materials contract. This unusual behavior enables thermal-expansion compensation in composites and supports high-dimensional stability in precision optics, microelectronics, and aerospace systems.

This database collects and organizes NTE-related materials and descriptors to make screening and comparison faster for researchers.

Descriptor Boundary

Universal classifier

ξ = G/Ẽ

NTE tendency: ξ < 2.84

PTE tendency: ξ ≥ 2.84

Physical Interpretation (From Methods)

Positive contribution α⁺

Bond stretching under anharmonic vibration contributes to thermal expansion.

α⁺ ∼ 1/Ẽ

Negative contribution α⁻

Soft transverse/shear phonons pull framework units inward.

|α⁻| ∼ 1/G

Competition result ξ

The ratio of the two mechanisms determines contraction or expansion tendency.

ξ = G/Ẽ

Classification Map

The map below illustrates the distribution of materials in the G-Ẽ space and the ξ = 2.84 boundary. Lower ξ regions are more likely to exhibit NTE behavior.

NTE classification figure based on shear-bond ratio

Citation

If you find this database or the descriptor framework useful in your research, please consider citing our work:

Guangming Chen, Shun Tian, Kaiwei Feng, Yilun Liu, Wanjian Yin, Qilong Gao, & Ke Zhou. (2026). A Universal Shear-Bond Descriptor and Machine-Learning Potentials Enable Large-Scale Discovery of Negative Thermal Expansion Materials. ChemRxiv.

https://chemrxiv.org/doi/full/10.26434/chemrxiv.15002572/v1

Authors & Contact

This database is maintained by: