Laetitia FarinacciÂ
Scanning tunnelling microscopy (STM) has established itself as the ultimate method for studying matter at the atomic scale. Importantly, through atom manipulation, one has perfect control over the atoms’ surroundings and can thus engineer spin coupling and magnetic interactions with ultimate precision. Here, we show that STM is also well suited for studying coherent spin dynamics at the atomic scale, providing a complementary perspective to ensemble studies. First, using STM combined with electron spin resonance (ESR), we demonstrate that we are able to tune the interaction between two Ti atoms on MgO/Ag(111) as a function of tip height. This subsequently allows us to probe the dynamics of the coupled atoms with DC pump-probe STM. Remarkably, we observe coherent dynamics at maximal entanglement, with the spin excitation flipping back and forth between the two atoms [1]. Next, we demonstrate that such coherent dynamics can also be observed between electron and nuclear spins within a single atom [2]. Finally, we turn our attention to coherent spin dynamics in 1D and quasi-1D structures and explore how these can be controlled and tuned at the atomic scale [3].
[1] Veldman et al., Science 372, 964-968 (2021). [2] Veldman et al., Nature Communications 15 (1), 7951 (2024). [3] in preparation.