Longitudinal dispersion and soliton in carbyne incorporating initial extension

We provide a modified Boussinesq equation to model the longitudinal motion of a linear monatomic carbon chain (carbyne). The modified model is achieved by applying the continuous approach to the force field that induces the initial extension and the bond length change. Our model implies that the initial extension significantly affects the dispersion relationship and the soliton’s profile. Specifically, the initial extension decreases the carbyne’s sound, phase, and group velocities. The initial extension also reduces the soliton’s wave height and flattens its shape. These new results imply that the initial extension can be used as a parameter to regulate wave propagation in one-dimensional atomic chains.