In the Comment, Cooper et al. pointed out a disagreement between two recent density functional theory (DFT) studies ([Li, Phys. Rev. B 85, 235407 (2012)] and [Cooper et al., Phys. Rev. B 87, 035423 (2013)]) on the uniaxial tensile stress as a function of the applied strain along the zigzag $\left(x\right)$ and armchair $\left(y\right)$ directions of single-layer ${\mathrm{MoS}}_2$. We show here that it is the in-plane atomic relaxation under the applied uniaxial tensile stress, rather than the errors in the execution of the DFT calculation, that leads to the discrepancy. Furthermore, through new analysis, we show that our original conclusion that the tensile strength of single-layer ${\mathrm{MoS}}_2$ is dictated by out-of-plane soft-mode phonon instability under the biaxial tension and the uniaxial tension along the armchair direction is still valid when the in-plane atomic relaxation is considered.

• Received 13 May 2014
• Revised 18 August 2014

DOI:https://doi.org/10.1103/PhysRevB.90.167402

Source: http://link.aps.org/doi/10.1103/PhysRevB.90.167402