  Magnetic atoms on superconductors induce localized Yu-Shiba-Rusinov (YSR)
bound states. The proposal that topological superconductivity and Majorana
modes can be engineered in arrays of hybridizing YSR states has led to their
intense investigation. Here, we study Majorana modes emerging from bands of
hybridized YSR states in artificially constructed Manganese (Mn) chains on
superconducting Niobium (Nb). By controlling the chain geometry on the single
atom level, we can measure the interaction-induced energy splitting of Majorana
modes from both chain's ends with increasing chain length. We find periodic
lengths where their interaction is tuned to zero within the experimental energy
resolution. Our work unravels ways to manipulate and minimize interactions
between Majorana modes in finite-size systems as required for Majorana-based
storage and processing of quantum information.
