Size-Dependent Structural Phase Transitions in SrTiO3 Nanoparticles

TL;DR

This study investigates how the structural phase transitions of SrTiO3 nanoparticles depend on particle size under pressure, revealing a stable polar phase in very small particles and size-dependent phase changes in larger ones.

Contribution

It provides new insights into the size-dependent structural phase behavior of SrTiO3 nanoparticles under pressure, relevant for device applications.

Findings

10 nm particles maintain polar structure up to 13 GPa

Larger particles undergo size-dependent cubic to tetragonal transition

Growth of 10 nm particles on mismatched substrates preserves polar state

Abstract

Understanding the structural phase diagram of nano scale SrTiO3 has important implications on the basic physics and applications of the general class of transition metal oxide perovskites. Pressure dependent structural measurements on monodispersed nanoscale SrTiO3 samples with average diameters of 10 to ~80 nm were conducted. A robust pressure independent polar structure was detected in the 10 nm sample for pressures of up to 13 GPa while a size dependent cubic to tetragonal transition occurs (at P = Pc) for larger particle sizes. The results suggest that the growth of ~10 nm STO particles on substrates with large lattice mismatch will not alter the polar state of the system for a large range of strain values, possibly enabling device use.