We have simulated the structural phase transition of one member of A2BX4 layered perovskitelike compounds, Rb2CaCl4. This family of compounds may be thought of as being constructed from normal perovskite unit cells but with a different stacking arrangement. In recent months, this structural family has become extremely important since it is the parent structure from which the new class of high-temperature superconductors comes from. The simulation was done using ab initio potentials with no adjustable parameters. Our calculations show a specific-heat anomaly at 400 K which corresponds to an observed pseudorotation of the CaCl6 octahedral group. This rotation is similar to the structural phase transitions observed in the perovskite-structure family. We also postulate a dynamically disordered high-temperature structure for this compound.
ASJC Scopus subject areas
- Condensed Matter Physics