Nair, M. NPalacio, IMascaraque Susunaga, ArantzazuMichel, E. G.Taleb-Ibrahimi, ATejeda, A.González Pascual, CésarMartin-Rodero, A.Ortega, J.Flores, F.2023-07-272023-07-272023-01-112469-995010.1103/physrevb.107.045303https://hdl.handle.net/20.500.14352/87349©2023 American Physical Society This work was supported by the French Agence Nationale de la Recherche (ANR), project SurMott, Ref. No. NT-09-618999. We acknowledge financial support from the Spanish Ministry of Science and Innovation through Projects No. MAT2017-88258-R, No. PID2021-123295NB-I00, No. PID2020-117024GB-C43, No. PID2021-125604NB-I00, and No. CEX2018-000805-M (María de Maeztu Programme for Units of Excellence in R&D). We also acknowledge the technical support provided by the Centro de Computación Científica-UAM (CCC-UAM), Project No. BIOFAST. We thank Professor D. Farías for many helpful discussions.We report an experimental and theoretical study of the electron-phonon coupling for alpha-Sn/Ge(111), a prototypical triangular lattice surface, closely related to Sn/Si(111)-( √3 x √3), where recent experimental evidence has found superconductivity [X. Wu et al., Phys. Rev. Lett. 125, 117001 (2020)]. We concentrate our study on the (3 x 3) phase of alpha-Sn/Ge(111) that appears between 150 and 120 K and has a well-known geometry with a half-filled electronic band around the Fermi energy. We show that this surface presents a giant electron-phonon interaction that can be considered at least partially responsible for the different phases that this system shows at very low temperature. Our theoretical results indicate that indeed the electron-phonon interaction in alpha-Sn/Ge(111)-(3 x 3) is unusually large, since we find that lambda, the electron mass enhancement for the half-filled band, is lambda = 1.3. This result is in good agreement with the experimental value obtained from high-resolution angle-resolved photoemission spectroscopy measurements, which yield lambda = 1.45 +/- 0.1engjournal article2469-9969https://journals.aps.org/prb/pdf/10.1103/PhysRevB.107.045303http://dx.doi.org/10.1103/PhysRevB.107.045303open access538.9Phase-TransitionSurfaceMaterials ScienceFísica de materiales2211 Física del Estado Sólido