Phase transformation of α -sheet borophene under thermal stimuli: molecular dynamics study of atomic mechanisms and heating rate effects

Abstract This study investigates the thermal effects on the structural stability of α -sheet borophene and predicts its melting behavior. In addition, the dependence of the phase transitions on the heating rate is also studied. Molecular dynamics simulations were employed to study the thermal evolution of the initial configurations across a wide temperature range. This approach enables the observation of atomic rearrangements and provides insight into the thermal stability of α -sheet borophene. In the initial configuration, the material was thoroughly characterized, revealing two distinct phase transitions during the heating process. A solid–liquid phase transition was identified at approximately 1783 K, while a solid–solid structural transformation from the α -sheet to a triangular structure was observed at 3466 K. When evaluating the effect of the heating rate, it was found that the onset of the solid–liquid transition occurred earlier, at 1508 K, in the second configuration. Furthermore, at around 4602 K, atoms with a coordination number (CN) of 6 became dominant, exceeding those in the original model at the same temperature, indicating enhanced structural transformation under slower heating conditions. Characteristic transformation temperatures were identified through the analysis of total energy per atom and heat capacity profiles. Phase transitions and their structural signatures were further confirmed through calculations of the radial distribution function, angular distribution, CN, and direct atomic visualization. Finally, comparative assessment of the two models indicates that a reduced heating rate accelerates structural evolution relative to the rate of temperature increase, demonstrating a significant influence of thermal ramping conditions on phase behavior.