Mechanical and electronic properties of monolayer MoS2 under elastic strain

We present our study on elastic constants and electronic structures of two-dimensional monolayer MoS2 under elastic strain using the first-principles calculations. The in-plane stiffness and Poisson's ratio calculated in the harmonic elastic strain range are found to be 123 N/m and 0.25, indicating that monolayer MoS2 is much softer than graphene. With the uniform strain applied, it is shown that the band gap of monolayer MoS2 undergoes a descent trend as strain increasing. Simultaneously, it is accompanied by two characteristic transitions, namely, direct-to-indirect transition at strain of 0.01 and semiconductor-to-metal transition at strain of 0.10. Furthermore, the effective mass of carriers is also modulated by the applied strain. (C) 2012 Elsevier B.V. All rights reserved.