We analytically study soliton excitations in a diatomic chain with different masses and alternating force constants between the nearest neighbors by the means of multiple scales plus quasi-discrete approximation method. This model simulates a row of atoms in the direction of a sphalerite-structure type of crystal. Considering the harmonic and quartic potential, we obtain the expressions of the stationary soliton solutions at some special wave vectors of the carrier wave (q=±π/a for acoustic mode and q=0,±π/a for optical mode). The configura...
