  Magnetic molecules on surfaces have been widely investigated to reveal
delicate interfacial couplings and for potential technological applications. In
these endeavors, one prevailing challenge is how to preserve or recover the
molecular spins, especially on highly metallic substrates that can readily
quench the magnetic moments of the ad-molecules. Here we use scanning tunneling
microscopy/spectroscopy to exploit the semimetallic nature of antimony and
observe, surprisingly yet pleasantly, that the spin of Co-phthalocyanine is
well preserved on Sb(111), as unambiguously evidenced by the emergent strong
Kondo resonance across the molecule. Our first-principles calculations further
confirm that the optimal density of states near the Fermi level of the
semimetal is a decisive factor, weakening the overall interfacial coupling,
while still ensuring sufficiently effective electron-spin scattering in the
many-body system. Beyond isolated ad-molecules, we discover that each of the
magnetic moments in a molecular dimer or a densely packed island is distinctly
preserved as well, rendering such molecular magnets immense potentials for
ultra-high density memory devices.
