%0 Journal Article
%T Ideal strength and phonon instability of strained monolayer materials
%A Eric B. Isaacs
%A Chris A. Marianetti
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevB.89.184111
%X The ideal strength of monolayer materials possessing semimetallic, semiconducting, and insulating ground states is computed using density functional theory. Here we show that, as in graphene, a soft mode occurs at the K-point in BN, graphane, and MoS$_2$, while not in silicene. The transition is first-order in all cases except graphene. In BN and graphane the soft mode corresponds to a Kekul{\'e}-like distortion similar to that of graphene, while MoS$_2$ has a distinct distortion. The phase transitions for BN, graphane, and MoS$_2$ are not associated with the opening of a band gap, which indicates that Fermi surface nesting is not the driving force. We perform an energy decomposition that demonstrates why the soft modes at the K-point are unique and how strain drives the phonon instability.
%U http://arxiv.org/abs/1311.1497v1