While the Born elastic stability criteria are well known for cubic crystals, there is some confusion in the literature about the form they should take for lower-symmetry crystal classes. Here we present closed form necessary and sufficient conditions for elastic stability in all crystal classes, as a concise and pedagogical reference to stability criteria in noncubic materials.

• Received 1 October 2014
• Revised 20 November 2014

DOI:https://doi.org/10.1103/PhysRevB.90.224104