In 2015 Griffin joined Jeffrey Neaton's laboratory at Lawrence Berkeley National Laboratory.[8] She recognized that multiferroic hexagonal manganites exhibited the same symmetry as those proposed shortly after the Big Bang, testing phenomena that occur on galactic scales with those that occur in a laboratory.[6][9] Her work explored symmetry-breaking conditions that lead to topological defects.[10][11] Griffin has also worked on materials for high-energy physics experiments.[12][13]
In 2023, she won the Early Career Scientist Prize in Computational Physics from the International Union of Pure and Applied Physics.[14] In the same year, Griffin published an arXiv preprint, presenting density functional theory augmented with a on-site Hubbard-like model (i.e., DFT+U) calculations of Cu-substituted lead phosphate apatite (i.e., suspected structure of LK-99), identifying correlated isolated flat bands at the Fermi level, a debated[15] signature of superconductors. Per the author,[16] this work did not show that LK-99 is a superconductor at room temperature, but suggested the possibility of a room temperature superconductivity. Her findings propose a simplified two-band model for understanding this behavior in LK-99, and potentially other superconductors.[17] Similar theory preprints by other academics and researchers did not entirely agree with Griffin's results. [18][19]
^Griffin, S. M; Lilienblum, M; Delaney, K; Kumagai, Y; Fiebig, M; Spaldin, N. A (2012). "From multiferroics to cosmology: Scaling behaviour and beyond in the hexagonal manganites". Physical Review X. 2 (4): 041022. arXiv:1204.3785. Bibcode:2012PhRvX...2d1022G. doi:10.1103/PhysRevX.2.041022.
^Griffin, Sinéad M. (30 July 2023). "Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite". arXiv:2307.16892 [cond-mat.supr-con].
^Cabezas-Escares, J.; Barrera, N. F.; Lavroff, R. H.; Cardenas, A. N. Alexandrova C.; Munoz, F. (2023). "Theoretical insight on the LK-99 material (Large update)". arXiv:2308.01135 [cond-mat.supr-con].
