Pressure-induced transition to the collapsed tetragonal phase in BaCr2As2

The structural and electronic properties of $\mathrm{BaC}{\mathrm{r}}_{2}\mathrm{A}{\mathrm{s}}_{2}$, which is isostructural to the 122 iron arsenide superconductors, are studied at high pressures using synchrotron x-ray powder diffraction, electrical resistivity measurements, and first-principles calculations. At a pressure of about 18.5 GPa, an isostructural phase transition to a collapsed tetragonal phase is observed, similar to that in $\mathrm{BaF}{\mathrm{e}}_{2}\mathrm{A}{\mathrm{s}}_{2}$. In both phases, $\mathrm{BaC}{\mathrm{r}}_{2}\mathrm{A}{\mathrm{s}}_{2}$ is a normal metal. Electronic structure calculations suggest a metallic and antiferromagnetic ground state with $G$-type magnetic order for the collapsed tetragonal phase.