Size dependence of the pressure-induced phase transition in nanocrystals

TL;DR

This paper extends the BOLS correlation mechanism to pressure effects, providing atomistic insights into how nanocrystals' phase stability depends on size and pressure, with validation on multiple materials.

Contribution

It introduces a novel application of the BOLS model to pressure-induced phase transitions in nanocrystals, linking atomic cohesive energy to size and pressure effects.

Findings

Size and pressure influence phase stability through competing effects.

The model accurately reproduces experimental data for CdSe, Fe2O3, and SnO2.

Atomic cohesive energy explains phase transition trends.

Abstract

Extending the recently-developed bond-order-length-strength (BOLS) correlation mechanism [Sun CQ, Prog Solid State Chem 2007, 35, 1-159] to the pressure domain has led to atomistic insight into the phase stability of nanostructures under the varied stimuli of pressure and solid size. It turns out that the competition between the pressure-induced overheating (TC elevation) and the size-induced undercooling (TC depression) dominates the measured size trends of the pressure-induced phase transition. Reproduction of the measured size and pressure dependence of the phase stability for CdSe, Fe2O3, and SnO2 nanocrystals evidences the validity of the solution derived from the perspective of atomic cohesive energy and its response to the external stimulus.