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O: Fachverband Oberflächenphysik

O 49: Poster: Nanostructures on Surfaces I

O 49.25: Poster

Dienstag, 13. März 2018, 18:15–20:30, Poster A

Transport-based single-atom STM electron-spin resonance: a cotunneling description — •Jose Reina¹, Nicolas Lorente¹, and Fernando Delgado² — ¹Centro de Física de Materiales (CFM-MPC) Centro Mixto CSIC-UPV/EHU, Manuel de Lardizabal 5, E-20018 San Sebastián, Spain. — ²Departamento de Física, Universidad de La Laguna, Instituto de estudios avanzados (IUdEA), Avda. Astrofísico Francisco Sánchez, S/N 38203 La Laguna (Tenerife), Spain

Electron spin resonance (ESR) has recently overcome its main limitation, reaching the single atom detection limit[1]. In its new form, magnetic resonance is observed as a variation of the current flowing through a scanning tunneling microscope tip positioned over a magnetic adatom while applying an ac. voltage of different frequencies. Although several theoretical origins of the ESR signal have been proposed [2], it is still unclear how the time-varying bias voltage couples to the localized spin, with marked discrepancies with the experimental observations. Here we show that this signal is associated to the variation of the potential energy felt by the electrons on its occupation of the adatom energy levels. Thus, by using a time-dependent cotunneling description of the transport, we estimate the STM-ERS driving strength and its dependence with the main control parameters of the ERS setup, making a close comparison with the experimental findings.

[1] S. Baumann et al., Science 350, 417 (2015)

[2] P. Berggren and J. Fransson, Sci. Rep. 6, 25584 (2016). J.L. Lado, A. Ferrón, and J. Fernández-Rossier, Phys. Rev. B 96, 205420 (2017)