Stability of the ternary perovskitesSc3EN(E=B,Al,Ga,In)from first principles

Mechanical and thermodynamic stability of the isoelectronic ternary inverse perovskites ${\text{Sc}}_3\text{EN}$ $\left(E=\text{B},\text{Al},\text{Ga},\text{In}\right)$ has been studied from first principles. We confirm stability of recently synthesized cubic phases ${\text{Sc}}_3\text{AlN}$ and ${\text{Sc}}_3\text{InN}$, and predict the stability of cubic ${\text{Sc}}_3\text{GaN}$ and a triclinic phase aP20-${\text{Sc}}_3\text{BN}$. Substantial phonon softening in ${\text{Sc}}_3\text{AlN}$ and ${\text{Sc}}_3\text{GaN}$ is observed indicating a possibility that structural defects could form readily. In accord, our experiments show that magnetron sputter deposited films contain regions with high density of nonperiodic stacking faults along the $⟨111⟩$ growth direction. We suggest that defect-free crystals may exhibit anomalies in the carrier properties, promising for electronic applications.