SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Mini-Symposium: Manipulation and control of spins on functional surfaces II
O 44.2: Vortrag
Dienstag, 2. März 2021, 14:00–14:15, R2
Free coherent evolution of a coupled atomic spin system initialized by electron scattering — Lukas M. Veldman1, •Laetitia Farinacci1, Rasa Rejali1, Rik Broekhoven1, Jeremie Gobeil1, David Coffey1, Markus Ternes2,3, and Alexander F. Otte1 — 1Delft University of Technology, The Netherlands — 2RWTH Aachen University, Germany — 3Peter-Grünberg-Institute, Jülich, Germany
Observing the free evolution of a coupled spin system is an essential step towards studying collective quantum spin dynamics, as well as gaining insight into the fundamental mechanisms leading to spin excitation. Here, we combine pump-probe and ESR techniques with STM to study the free evolution of a single atomic spin depending on its level of entanglement with a second one. We build TiH dimers on MgO/Ag(100) in which the two spins are inherently detuned. We then make use of the magnetic interaction with the STM tip to tune the level of entanglement between the two spins: using ESR, we characterize the energy diagram of the dimer and identify the tip height at which both spin precess at the same frequency. Subsequently, we use a pump-probe scheme to, first, initialize the system via an electron induced spin excitation and, second, study the free evolution of the spin under the tip. We show that only when the two spins entangle, the excitation is swapped back and forth at a frequency that is given by their coupling strength. These results provide insight into the locality of electron-spin scattering: only the spin directly underneath the tip is affected, irrespective of its global quantum state.