SFB 1238 | April 26, 14:30
Dynamics of atomic spins - from the propagation of a spin excitation to dynamics mediated by the hyperfine interaction
The combination of electron spin resonance and scanning tunneling microscopy drastically widened the range of interactions that can be studied on the atomic scale [1]. Overcoming the energy resolution of typical scanning tunneling spectroscopy by 3 orders of magnitude, it has been used to characterize both dipolar and exchange interactions between single spins [2], tune their level of entanglement [3] and even resolve the hyperfine interaction of single atomic spins [4]. In this talk I will first discuss how studying the anisotropy of the hyperfine interaction can be used to determine the electronic ground state of TiH/MgO/Ag(100), a feature that so far eluded experimentalists [5]. The second part of the talk will be devoted to the study of dynamics of atomic spins. We first demonstrate that a DC-pump-probe scheme can be used to study the free evolution of two coupled atomic spins: by controlling their level of entanglement, we find a tuning point in which a spin excitation is swapped back and forth between them [6]. This is then used as the basis for a larger study of the free propagation of spin excitations within atomic chains and quasi-2D structures [7]. Finally, I will discuss our most recent experiment in which the size of the system is reduced to a single atom: using the same technique we intend to gain insight into the dynamics between a single electron and a nuclear spin mediated via the hyperfine interaction [8]. [1] Baumann et al., Science 350, 6259 (2015) [2] Choi et al., Nat. Nano 12, (2017) [3] Yang et al., Phys. Rev. Lett. 119, 227206 (2017) [4] Willke et al., Science 362 (2018) [5] Farinacci, et al., Nano Letters 22, 8470 (2022) [6] Veldman et al., Science 372, 6545 (2021) [7] Veldman et al., in preparation [8] Veldman et al., in preparation
FU Berlin
Seminar Room of the Institute of Physics II
Contact: Erwann Bocquillon