Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 21: Focus Session: Spins on Surfaces studied by Atomic Scale Spectroscopies III
O 21.5: Vortrag
Dienstag, 19. März 2024, 11:45–12:00, MA 004
DC-bias gating of single spin electron paramagnetic resonance — Hong T. Bui1,2, We-hyo Seo1,2, Valeria Sheina1,2, and •Soo-hyon Phark1,2 — 1Center for Quantum Nanoscience, Institute for Basic Science, Seoul, Korea — 2Ewha Womans University, Seoul, Korea
Ti and Fe atoms in the tunnel junction of a scanning tunneling microscope combined with electron paramagnetic resonance (EPR) are prototypical quantum systems to study single spin dynamics. However, influence of DC electric bias (Vdc), followed by the spin-polarized current passing through the spins, on the EPR signal have not been studied in depth yet. Here, we introduce DC-bias gating of EPR resonance observed from single Ti and Fe adsorbates on ultrathin MgO layers. We find that a negative Vdc, inducing reversed magneto-tunneling transport, considerably suppresses EPR of Ti and accompanies a reversal of peak asymmetry. This is even more pronounced in the EPR of Fe, where the sign of the peak is inversed with a considerable intensity. Simulations on spin-dependent electron transport through a RF-driven single spin reproduce the experiments on both Ti and Fe in good agreement, revealing that DC-bias-driven spin pumping via the inelastic channels plays a key role in the RF-driven spin dynamics of the EPR-relevant two levels. In addition, a long-lived inversed population in a Fe spin can promote EPR resonance with a reversed sign as observed in the measured spectra.