Academic Affiliation: University of Stuttgart, Institute for Functional Matter and Quantum Technologies

Date and Time of the Talk: Sept 14th, 2021; 17:00 – 19:00 (KST)

New insights into spin dynamics – Stochastic resonance as a tool

Stochastic scattering between magnetic atoms and electrons of a metal shortens excitation lifetimes and accelerates decoherence. However, this scattering also creates characteristic time scales, that carry information about dynamics of the system. Modulating the scattering close to a threshold leads to frequency-dependent synchronization of the spin of the magnetic atoms and the modulation [1]. This
effect, known as Stochastic Resonance, amplifies the dynamic response to the modulation and can be used to investigate quantum fluctuations of the system [2]. Here we introduce a measurement technique which uses the synchronization effect that underlies Stochastic Resonance to control and measure characteristic time scales of magnetic atoms with a scanning tunneling microscope. This enables the investigation of spin dynamics in a bandwidth ranging from milliseconds to picoseconds. In some spin structures this reveals multiple switching paths between higher excited states, thus providing insight into new, previously inaccessible dynamics.

[1] Hänze et al., Sci. Adv. 2021, 7 (2021).
[2] R. Löfstedt, S. N. Coppersmith, Phys Rev. Lett. 72, 1947 (1994)