Single lanthanide atoms and molecules are promising candidates for atomic data storage
and quantum logic due to the long lifetime of their magnetic quantum states. Accessing and
controlling these states through electrical transport requires precise knowledge of their
electronic configuration at the level of individual atomic orbitals, especially of the outer shells
involved in transport. However, no experimental techniques have so far shown the required
sensitivity to probe single atoms with orbital selectivity. Here we resolve the magnetism of …

Surface-adsorbed atoms with long magnetic lifetimes, also called single atom magnets, are
the smallest unit of matter that can be used to store and manipulate information [Science
352, 318 (2016), Nature 543, 226 (2017)]. Hence, they represent the ultimate limit of
downscaling for magnetic storage devices. In order to store and process information, it is
required to tailor their magnetic states such to stabilize the electron spin orientation against
thermal and quantum fluctuations [Phys. Rev. Lett. 121, 027201 (2018), Phys. Rev. Lett. 124 …