The indirect L-valleys splitting inductive optical gain variation of nanowires caused by [110] direction uniaxial stress.

We calculate the band structures of nanowires under the [110] direction stress via the effective-mass theory. Interestingly, it is found that octuple equivalent indirect L-valleys can be split into -valleys and -valleys with quadruple degeneracy by the imposed stress, which results in the inflection point of electron filling ratio at the direct -valley whether Sn content is low or high. Moreover, the optical gain along the z direction will not only appear an inflection point, but also can be enhanced several times with the increase of the stress, which will be much greater than that along the x direction.