Effect of anisotropic interactions on the heat conduction of one-dimensional chains

One-dimensional (1D) chain models are frequently employed to investigate heat conduction in various systems. Despite their widespread use, there has been limited exploration of 1D chain models with anisotropic interactions. In this study, we examine heat conduction in a 1D chain model with orientation-position coupled interaction, namely the compressible XY model, and compare it with isotropic Fermi-Pasta-Ulam-Tsingou beta (FPUT-beta) systems. At low temperatures, the local temperatures in the translational and rotational degrees of freedom differ due to the difference in the contact thermal resistance in the two degrees of freedom. The system maintains orientational order, and the orientation-position-coupling effect lowers thermal conductivity in translational degrees of freedom. As the temperature rises above a transition point, the rotation of particles switches from oscillation to diffusion, leading to a solid-like to fluid-like transition in the rotational degree of freedom. The anisotropic interactions become negligible under time averaging, making the system's properties similar to those of isotropic FPUT-beta systems. Additionally, we investigate the system's orientational structure to elucidate this transition. These findings will enhance our understanding of the dynamics of nanoscale anisotropic systems, such as the heat conduction of spin chains.