High-Pressure Behavior of Ca2SnO4, Sr2SnO4, and Zn2SnO4

Abstract

The pressure-induced structural evolution of Ca₂SnO₄, Sr₂SnO₄, and Zn₂SnO₄ has been characterized by powder X-ray diffraction up to 20 GPa using the ALBA synchrotron radiation source and density functional theory calculations. No phase transition was observed in Ca₂SnO₄ and Zn₂SnO₄ in the investigated pressure range. The observation in Zn₂SnO₄ solves contradictions existing in the literature. In contrast, a phase transition was observed in Sr₂SnO₄ at a pressure of 9.09 GPa. The transition was characterized as from the ambient-condition tetragonal polymorph (space group I4/mmm) to the low-temperature tetragonal polymorph (space group P4₂/ncm). The linear compressibility of crystallographic axes and room-temperature pressure-volume equation of state are reported for the three compounds studied. Calculated elastic constants and moduli are also reported as well as a systematic discussion of the high-pressure behavior and bulk modulus of M₂SnO₄ stannates.