Application Of GPU-Accelerated Molecular Dynamics Simulation In Low-Dimensional Thermal Transport

Low-dimensional materials have attracted widespread attention because of their unique thermal and mechanical properties.With the dev·elopment of nanoelectronic devices,there has higher requirements for thermal transport properties of materials.Due to the high cost in preparation as well as the difficulties in experimentation,the molecular dynamics simulation method has become the main means to investigate heat conduction in law of low-dimensional materials.In the macroscopic system,heat conduction of materials follows Fourier's law,but Fourier's law is no longer applicable in the low-dimensional system.Thermal conductivity in one-dimensional materials diverges the system size as the power-law,but the divergence law of two-dimensional materials is controversial.The main reason for the divergence is the inconsistent simulative results depending on the size effect in the two-dimensional system.In comparision with one-dimensional system,the traditional method of simulating the heat conduction in two-dimensional materials faces the problem of large scale system size and long-time simulations.Therefore,to improve the simulation calculation efficiency of two-dimensional materials is an urgent task for the research of the heat conduction in low-dimensional materials.GPU(graphic process unit)has been widely used in computational chemistry,computational finance,machine learning,and other fields because of its powerful floating-point computing power and ultra-high memory bandwidth.With the outstanding parallel performance of GPU in high-performance computing,the application of GPU acceleration in more and more subject areas has achieved remarkable results.In the study of heat transfer of low-dimensional materials,there is only one-dimensional GPU accelerated heat transfer algorithm,and the use of GPU acceleration has not been popularized.Applying GPU acceleration to the field of two-dimensional system heat conduction research is an inevitable trend.In this work,we studied the GPU-accelerated molecular dynamics simulation of two-dimensional heat conduction algorithm,and successfully apply GPU acceleration to the calculation of the heat conduction law of two-dimensional systems,and solve some unsolved or controversial problems in large-scale low-dimensional systems.The problem is to use the conclusions obtained to guide the thermal conductivity control of low-dimensional materials and the engineering application of various aspects of low-dimensional materials.We have calculated three different sizes of two-dimensional momentum conservation systems,including FPU-?,FPU-quartic,and XY systems.Through the calculation of their dynamic diffusion laws,we observe the dimensional transformation process of the system from one dimension to two dimensions,and find that the heat conduction of the two-dimensional momentum conservation system diverges with the power law of the system size.In addition,we have also found that unlike the one-dimensional system,the normal momentum diffusion behavior in the two-dimensional system can also bring about the abnormal energy diffusion of the system.In addition,we calculate the non-conservative(?)4 system of different sizes,which demonstrates that the conservation of momentum is a key factor in whether the system can exhibit normal heat conduction behavior in either one-dimensional or two-dimensional situations.It has important guiding significance for the application of low-dimensional materials in heat dissipation,thermal rectification,semiconductor materials and performance improvement and prediction of thermoelectric materials.