Fast spin and charge dynamics at the single atom level

Dr. Sebastian Loth - Max Planck Institute for the Structure and Dynamics of Matter, Hamburg, Germany

Spin and charge correlations are particularly pronounced in nanoscale materials where they give rise to exciting many-body effects such as colossal responses to minimal electronic fluctuations or quantum critical behavior. Accessing these correlations on their intrinsic length and time scales is an important step towards a microscopic understanding of correlated-electron physics.
We combine scanning tunneling microscopy with electronic and optical pump probe schemes to achieve ultrafast spectroscopy of spin and charge dynamics with atomic spatial resolution. We reach nanosecond time resolution with all-electronic pump-probe spectroscopy [1] and picosecond time resolution by excitation of the tunnel junction with Terahertz light pulses.
In this talk I will focus on two recent experiments: one in which we probed the fast charging dynamics of individual dopants in silicon through highly localized field effect gating [2] and one in which we fabricated a few-atom spin sensor capable of measuring micro-electronvolt magnetic interaction with nearby nanomagnets [3].
These experiments shed light onto the impact of correlations and coherences in quantum materials highlight pathways to design and control magnetism at the single atom level.

[1] S. Loth, M. Etzkorn, C. P. Lutz, D. M. Eigler, A. J. Heinrich, Science 329, 1628 (2010).
[2] M. Rashidi, J. Burgess, M. Taucer, R. Achal, J. Pitters, S. Loth, R. Wolkow, arXiv: 1512.01101 (2015).
[3] S. Yan, L. Malavolti, J. Burgess, S. Loth, arXiv: 1601.02723 (2016).

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