  Proximity effect facilitates the penetration of Cooper pairs that permits
superconductivity in normal metal, offerring a promising approach to turn
heterogeneous materials into superconducting and develop exceptional quantum
phenomena. Here, we have systematically investigated proximity-induced
anisotropic superconductivity in monolayer Ni-Pb binary alloy by combining
scanning tunneling microscopy/ spectroscopy(STM/STS) with theoretical
calculations. By means of high temperature growth, the(3root3by3root3)R30o
Ni-Pb surface alloy has been fabricated on the Pb(111), where the appearance of
domain boundary as well as lattice transformation are further corroborated by
the STM simulations. Given the high spatial and energy resolution, tunnelling
conductance (dI/dU) spectra have resolved a reduced but anisotropic
superconducting gap NiPb about 1.0 meV, in stark contrast to the isotropic Pb
about 1.3 meV on the conventional Pb(111). In addition, the higher density of
states at Fermi energy (D(EF)) of Ni-Pb surface alloy results in an enhancement
of coherence peak height. According to the same Tc about 7.1 K with Pb(111)
from the temperature dependent NiPb and a short decay length Ld about 3.55 nm
from the spatially monotonic decrease of NiPb, both results are supportive for
the proximity-induced superconductivity. Despite a lack of bulk counterpart,
the atomic-thick Ni-Pb bimetallic compound opens a new pathway to engineer
superconducting properties down to the low-dimensional limit, giving rise to
the emergence of anisotropic superconductivity via proximity effect.
