Coherent control of a single Er electron spin on surface

Electron spins on surface provide an atomic scale qubit platform for quantum information science using scanning tunneling microscopy (STM) [1,2]. A bottleneck of this new platform lies in the decoherence stemming from the strong interaction with the environments. Lanthanide atoms, with their highly localized 4f electrons, offer a potential solution to this issue and make them as strong candidates of single atomic spin qubits on surfaces with a high quality factor Q = 2ΩT₂ (Ω = Rabi rate, T₂ = coherence time). In this talk, we present a recent advance in the qubit quality factor, achieved using erbium (Er) atoms on a MgO surface [3]. We performed a coherent control of the Er atoms using pulsed electron spin resonance (ESR), sensed by a nearby Ti spin [4]. Notably, a single Er spin showed a fivefold improvement in the qubit quality factor compared to the prototypical Ti spin on the same substrate [5]. This result represents a step towards implementing quantum processes into atomic spin qubits on surfaces.

[1] Soo-hyon Phark et al. ACS Nano 17, 14144 (2023).

[2] Yu Wang et al. Science 382, 87 (2023).

[3] Stefano Reale et al. Phys. Rev. B 107, 045427 (2023).

[4] Stefano Reale et al. Nat. Commun. 15, 5289 (2024).

[5] K. Yang et al. Science 366, 509-512 (2019).