Thermally driven classical Heisenberg chain with a spatially varying magnetic field: Thermal rectification and Negative differential thermal resistance

摘要

Thermal rectification and negative differential thermal resistance are twoimportant features that have direct technological relevance. In this paper, westudy the classical one dimensional Heisenberg model, thermally driven by heatbaths attached at the two ends of the system, and in presence of an externalmagnetic field that varies monotonically in space. Heat conduction in thissystem is studied using a local energy conserving dynamics. It is found that,by suitably tuning the spatially varying magnetic field, the homogeneoussymmetric system exhibits both thermal rectification and negative differentialthermal resistance. Thermal rectification, in some parameter ranges, showsinteresting dependences on the average temperature T and the system size N -rectification improves as T and N is increased. Using the microscopic dynamicsof the spins we present a physical picture to explain the features observed inrectification as exhibited by this system and provide supporting numericalevidences. Emergence of NDTR in this system can be controlled by tuning theexternal magnetic field alone which can have possible applications in thefabrication of thermal devices.