Quantum-mechanical study of the impact of thermal vibrations on the stability of the FeSn2 intermetallics
| Authors | |
|---|---|
| Year of publication | 2024 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | FRIÁK, Martin, Petr ČÍPEK, Pavla ROUPCOVÁ, Oldřich SCHNEEWEISS, Jana PAVLŮ, Dominika FINK, šárka MSALLAMOVÁ and Alena MICHALCOVÁ. Quantum-mechanical study of the impact of thermal vibrations on the stability of the FeSn2 intermetallics. In NANOCON. 2024. |
| Description | We have performed a combined theoretical and experimental study of FeSn2 intermetallics. We were motivated by a scarcity of published data as well as previous theoretical calculations of the antiferromagnetic (AFM) state of FeSn2, when this compound was found mechanically unstable due to imaginary-frequency phonons, i.e., effectively denying the existence of FeSn2. Addressing both mechanical and thermodynamic stability within density-functional theory (DFT) calculations, we focused on the AFM state as well as the ferromagnetic (FM) state of FeSn2, which were both considered in earlier experiments. In contrast to the previous calculations, we found the AFM FeSn2 state mechanically stable (no imaginary-frequency phonons). The same is true for the FM state, which possesses a slightly higher energy than the AFM state. The mechanical stability allowed for assessing the thermodynamic properties within both harmonic approximations as well as computationally much more demanding quasi-harmonic approximation. Interestingly, while the static-lattice formation energy of AFM FeSn2 is negative and, therefore, the compound is predicted stable with respect to the decomposition into elemental end-members, phonon-related contributions have a destabilizing impact at low temperatures. Our calculations were complemented by experimental characterization of Fe-Sn samples and the experimental FeSn2 lattice parameters were found in excellent agreement with theoretical values. |
| Related projects: |