Melting curve of tin to 61 GPa: Resolving discrepancies through shock experiments and simulations
Phys. Rev. B 112, 024110 – Published 22 July, 2025
DOI: https://doi.org/10.1103/l1qh-5c44
Abstract
Tin (Sn), a well-known element intensively studied for its multiple structural transformations under pressure, exhibits unclear high-pressure melting behavior with limited dynamic experimental data. This study combines shock compression experiments using lithium fluoride (LiF) and magnesium oxide (MgO) transparent windows with ab initio molecular dynamics (AIMD) simulations to determine the melting curve of Sn up to 61 GPa. The shock melting data of Sn from 34 to 44 GPa were determined using LiF window and extended to 61 GPa using MgO window, leveraging MgO's impedance matching with Sn to probe near-Hugoniot release states. Dynamic emissivity and radiance were measured simultaneously at the Sn/window interface using a multichannel pyrometry system, enabling accurate temperature determination under shock release conditions. A consistent melting curve was determined by the dynamic experiments and AIMD calculations using Z method, in agreement with the results of other dynamic measurements in the pressure range of 10–39 GPa. The results reconcile the recently reported static measurements and theoretical discrepancies, and provide a reliable melt boundary for establishing a physical model of Sn at extremes. Our direct shock measurements with simultaneous emissivity-radiance diagnostics and atomic-scale simulations have implications for resolving high-pressure melting behavior of other multivalent metals.
