Mapping Orbital-Resolved Magnetism in Single Lanthanide Atoms

Abstract

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 individual orbitals in Gd and Ho single atoms on MgO/Ag(100) by combining X-ray magnetic circular dichroism with multiplet calculations and density functional theory. In contrast to the usual assumption of bulk-like occupation of the different electronic shells, we establish a charge transfer mechanism leading to an unconventional singly ionized configuration. Our work identifies the role of the valence electrons in determining the quantum level structure and spin-dependent transport properties of lanthanide-based nanomagnets.

Metamagnetic transition and a loss of magnetic hysteresis caused by electron trapping in monolayers of single-molecule magnet Tb2@C79N

“…The persistence of the afm state on h-BN| Rh (111) and MgO|Ag(100) could serve as an indication that the charge transfer from the substrate is not the reason for the unexpected magnetic behavior of Tb 2 @C 79 N. However, the charge transfer hypothesis still cannot be fully excluded by these data because there are examples of the electron transfer between Ag and adsorbate on MgO|Ag(100) substrates. [98][99][100][101][102][103][104] For instance, pentacene molecules acquire one electron when deposited onto MgO(2 ML)|Ag (100). 99 Variation of the MgO layer thickness and work-function resulted in the co-existence of neutral and charged pentacene molecules, and signatures of the charge transfer were observed up to the MgO thickness of 16 ML.…”