%0 Journal Article %A Nair, M. N %A Palacio, I %A Mascaraque Susunaga, Arantzazu %A Michel, E. G. %A Taleb-Ibrahimi, A %A Tejeda, A. %A González Pascual, César %A Martin-Rodero, A. %A Ortega, J. %A Flores, F. %T Giant electron-phonon interaction for a prototypical semiconductor interface: Sn/Ge(111)-(3 x 3) %D 2023 %@ 2469-9950 %U https://hdl.handle.net/20.500.14352/87349 %X 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 +/- 0.1 %~