Nuclear magnetic resonance on a single atom with a local probe

Atomic nuclear spins are promising candidates in the development of quantum information technologies on a wide variety of physical platforms. Thanks to the high degree of isolation from their environment, nuclear spins show long-lived spin states, but this also poses challenges on their control and readability. Detailed characterization and control over the atomic-scale environment of the nuclear spin become of great importance for their efficient control. In this work, using scanning tunnelling microscopy, we reveal nuclear magnetic resonance on a single on-surface atom. We employ an electron-nuclear double resonance measurement scheme and resolve nuclear spin transitions of a single 47Ti isotope with a nuclear spin of I = 5/2. Our measurements and numerical analysis reveal the nature of hyperfine and quadrupole couplings of the studied system. We also show our ability to address the nuclear spin in the limit of weak hybridization with the electron spin, a requirement for direct control of the nuclear spin in the long-lifetime regime. This investigation of an atomic nuclear spin in a platform with atomic-scale control is a valuable development for other platforms deploying nuclear spins. Nuclear magnetic resonance of individual on-surface atoms has relied on electron-nuclear spin hybridization. Here, the authors use electron-nuclear double resonance with a scanning tunnelling microscope to resolve nuclear-spin transitions of a single atom on a surface in the weak-hybridization regime.