Anomalous temperature dependent heat transport in one-dimensional momentum-conserving systems with soft-type interparticle interaction

Abstract

To date, most of the theoretical and numerical studies on heat transport are only focused on the systems whose interparticle interactions are usually Fermi-Pasta-Ulam (FPU) like and hard-type (HT). Here we investigate how the transport behavior would be changed when the soft-type (ST) interaction is considered. We find that with the increase of system's temperature, introducing the ST interaction softens phonons and decreases their velocities, while this type of nonlinearity, similarly to its counterpart of HT, cannot fully damp the longest wave phonons. Therefore, an anomalous temperature dependent heat transport with certain scaling behavior similarly to those in the FPU-like systems with HT interactions can be seen. Our detailed examination from simulations well verify this temperature dependent behavior.