FEATURES OF STRUCTURE AND PROPERTIES IN GaBi DEMIXING MELT: EXPERIMENT AND MOLECULAR DYNAMICS METHOD

The temperature dependence of the dynamic viscosity of the demixing melt of critical composition GaBi was measured by the method of damped torsional oscillations in the continuous cooling mode at a rate of 3 K/min from 1200 K to the critical temperature T and at a rate of 0.5 K/min from 600 K to T. It was found that the viscosity of this melt deviates from the Arrhenius dependence in the range of 14 K above the critical point. Molecular dynamics simulation of the GaBi melt was carried out using the ANN potential. The initial training set was obtained by the ab initio MD method for a cell of 500 particles in the VASP package. The final training set was obtained using active machine learning in the DPGEN package. Based on these data, the ANN potential was trained in the DeepMD package. This potential was then used for simulations in the LAMMPS package for a system of 13,500 particles with a time step of 2.5 fs. The obtained potential was used to calculate the partial pair correlation functions, partial coordination numbers, diffusion coefficients and density of the melt of the critical composition GaBi. The partial radial distribution functions, density and diffusion coefficients were calculated in the isothermal mode in the range from 300 to 1300 K with a step of 200 K. The partial coordination numbers were obtained in the continuous cooling mode at a rate of 10 K/s in the range of 400-800 K. An anomalous behavior of the partial coordination numbers was found, which begins at a temperature very close to the critical point. Anomalies were also found in the partial radial distribution functions near the critical temperature. No features were revealed in the temperature dependences of the calculated diffusion coefficients.