Wave\nFunction Engineering on Superconducting Substrates:\nChiral Yu-Shiba-Rusinov Molecules

Magnetic adatoms\non superconductors give rise to Yu-Shiba-Rusinov\n(YSR) states that hold considerable interest for the design of topological\nsuperconductivity. Here, we show that YSR states are also an ideal\nplatform to engineer structures with intricate wave function symmetries.\nWe assemble structures of iron atoms on the quasi-two-dimensional\nsuperconductor 2<i>H</i>-NbSe<sub>2</sub>. The Yu-Shiba-Rusinov\nwave functions of individual atoms extend over several nanometers\nenabling hybridization even at large adatom spacing. We show that\nthe substrate can be exploited to deliberately break symmetries of\nthe adatom structure leading to hybridized YSR states exhibiting symmetries\nthat cannot be found in orbitals of iso-structural planar molecules\nin the gas phase. We exploit this potential by designing chiral YSR\nwave functions of triangular adatom structures. Our results significantly\nexpand the range of interesting quantum states that can be engineered\nusing arrays of magnetic adatoms on superconductors.