Pressure Induced Structural Phase Transitions in SrTiO$_{\mathrm{3}}$ Nanoparticles

Bulk SrTiO$_{\mathrm{3}}$ (STO) is paraelectric and exhibits a structural phase transition at a pressure, P\textasciitilde 6 GPa, at room temperature. However nanoscale STO is not well explored. Pressure dependent structural measurements on monodispersed nanoscale SrTiO$_{\mathrm{3}}$ samples with average diameters of 10 to \textasciitilde 80 nm were conducted to enhance the understanding of the structural phase diagram of nanoscale SrTiO$_{\mathrm{3}}$. A robust pressure independent polar structure was detected in the 10 nm sample for pressures up to 13 GPa while a size dependent cubic to tetragonal transition occurs (at P $=$ P$_{\mathrm{c}})$ for larger particle sizes. This work is supported by DOE Grant. DE-FG02-07ER46402.