Abstract
The latent heat, L, is central to melting, but its atomic origin remains elusive. It is proportional to the entropy of fusion, ΔSfus = L/Tm (Tm is the melting temperature), which depends on changes of atom configurations, atom vibrations, and thermal electron excitations. Here, we combine inelastic neutron scattering and machine-learned molecular dynamics to separate ΔSfus into these components for Ge, Si, Bi, Sn, Pb, and Li. When the vibrational entropy of melting, ΔSvib, is zero, ΔSfus ≃ 1.2 kB per atom. This result provides a baseline for ΔSconfig and nearly coincides with “Richard’s Rule” of melting. The ΔSfus deviates from this value for most elements, however, and we show that this deviation originates with extra ΔSvib and extra ΔSconfig. These two components are correlated for positive and negative deviations from Richard’s rule – the extra ΔSconfig is consistently ~ 80% of ΔSvib. Our results, interpreted with potential energy landscape theory, imply a correlation between the change in the number of basins and the change in the inverse of their curvature for the melting of pure elements.
| Original language | English |
|---|---|
| Article number | 271 |
| Journal | Communications Materials |
| Volume | 5 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2024 |
Funding
The authors thank S. Mudide for assisting in sample preparation, R. Mills for their input on sample containment, and H. L. Smith for conversations on quasielastic fitting. Research at Oak Ridge National Laboratory\u2019s Spallation Neutron Source (SNS) was sponsored by the Scientific User Facilities Division, Basic Energy Sciences (BES), Department of Energy (DOE). This work used resources from the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract DE-AC02-05CH11231. This work was supported by the DOE Office of Science, BES, under Contract DE-FG02-03ER46055.