Experimental Chemistry and Structural Stability of AlNb₃ Enabled by Antisite Defects Formation.

First-principles evolutionary algorithms are employed to shed light on the phase stability of Al⁻Nb intermetallics. While the tetragonal Al₃Nb and AlNb₂ structures are correctly identified as stable, the experimentally reported Laves phase of AlNb₃ yields soft phonon modes implying its dynamical instability at 0 K. The soft phonon modes do not disappear even upon elevating the temperature in the simulation up to 1500 K.