Synthesis of samarium nitride thin films on large-lattice mismatch substrates using molecular beam epitaxy

New nuclear energy paradigms require an in-depth understanding of new fuel and cladding materials. Lanthanide- and actinide-based nitride compounds are an understudied group of materials compared to their oxide counterparts, which provide new avenues for nuclear reactor designs. Their 4f and 5f electron shell gives rise to a variety of interesting physics such as unconventional superconductivity. Samarium nitride (SmN) has been recently identified as a material where ferromagnetic order and p-type superconductivity coexist. Our team will present results on the growth conditions of pure and doped SmN using molecular beam epitaxy, known for its high-quality synthesis ability of new materials [1], and its electronic transport properties as a function of temperature and magnetic field. The large lattice mismatch between film and the MgO substrate (~20%) is alleviated through a thin defect layer formed at the interface, that allows for a highly ordered, crystalline film on top. The resulting SmN is highly resistive, and preserves the registry of the substrate [2].

[1] Vallejo, Kevin D., et al. "Tensile-strained self-assembly of InGaAs on InAs (111) A." Journal of Vacuum Science & Technology B 39.6 (2021).

[2] Vallejo, Kevin D., et al. "Synthesis of Samarium Nitride Thin Films on Magnesium Oxide (001) Substrates Using Molecular Beam Epitaxy." Crystals 14.9 (2024): 765.