  Magnetic impurities have a dramatic effect on superconductivity by breaking
the time-reversal symmetry and inducing so-called Yu-Shiba-Rusinov (YSR) low
energy bound states within the superconducting gap. The spatial extent of YSR
states is greatly enhanced in 2D systems, which should facilitate the formation
of coupled states. Here, we observe YSR states on single cobalt phthalocyanine
(CoPC) molecules on a 2D superconductor NbSe$_2$ using low-temperature scanning
tunneling microscopy (STM) and spectroscopy (STS). We use STM lateral
manipulation to create controlled CoPc dimers and demonstrate the formation of
coupled YSR states. The experimental results are corroborated by theoretical
analysis of the coupled states in lattice and continuum models. Our work forms
an important step towards the realization of exotic topological states in
designer magnetic lattices.
