Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 34: Poster Tuesday: Scanning Probe Techniques 2

O 34.2: Poster

Tuesday, September 6, 2022, 11:00–13:00, P3

Determining the phase transfer function of an STM for coherent spin operations — •Evert Stolte — TU Delft

Coherent control of single spin transitions in atoms on a surface has been achieved with electron spin resonance scanning tunnelling microscopy (ESR-STM).[1] Extending that control to a series of sequential gates on different transitions and developing more complex gates requires radio frequency (RF) pulses at different frequencies with controlled relative amplitudes and phases, which are both affected by the transfer function of the power line to the tunnel junction. While the amplitude transfer function can be determined through a well-described rectification procedure [2], characterizing the phase transfer function remains challenging. Straightforward transmission or reflection measurements are excluded as it is not possible to separate phase rotations incurred on the way into the STM from those happening on the outward journey.

Here we report on the development of an in-situ method to determine the phase transfer function at radio frequencies that can be readily implemented to standard ESR-STM setups. The method is based on the envelope detection of the beat signal that is generated by adding two continuous wave RF signals separated by an audio frequency. The effectivity of the procedure is tested through pump-probe autocorrelation measurements with square pulses, which should show a reduced minimum width if the phase correction is successful.

[1] Yang, K. (2019). Science, 366(6464), 509-512.

[2] Paul, W. (2016). Review of Scientific Instruments, 87(7).