  The induced superconductivity (SC) in a robust and scalable quantum material
with strong Rashba spin-orbit coupling is particularly attractive for
generating topological superconductivity and Majorana bound states (MBS). Gold
(111) thin film has been proposed as a promising candidate because of the large
Rashba energy, the predicted topological nature and the possibility for
large-scale MBS device fabrications. We experimentally demonstrate two
important steps towards achieving such a goal. We successfully show induced SC
in the Shockley surface state (SS) of ultrathin Au(111) layers grown over
epitaxial vanadium films, which is easily achievable on a wafer scale. The
emergence of SC in the SS, which is physically separated from a bulk
superconductor, is attained by indirect quasiparticle scattering processes
instead of by conventional interfacial Andreev reflections. We further show the
ability to tune the SS Fermi level (E_F) by interfacing SS with a high-k
dielectric ferromagnetic insulator EuS. The shift of E_F from ~ 550 mV to ~34mV
in superconducting SS is an important step towards realizing MBS in this robust
system.
