Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 35: Acoustic Waves and Nanomechanics
HL 35.2: Talk
Thursday, September 8, 2022, 15:15–15:30, H34
Determining Amplitudes of Standing Surface Acoustic Waves via Atomic Force Microscopy — •Jan Hellemann1, Filipp Müller1, Madeleine Msall2, Paulo V. Santos1, and Stefan Ludwig1 — 1Paul-Drude-Institut für Festkörperelektronik, Berlin, Deutschland — 2Bowdoin College, Maine, USA
Our aim is the realization of strong coupling between cavity phonons and a few electron double quantum dot as an on-chip hybrid system for quantum information applications. For this purpose, we develop radio frequency surface-phonon cavities containing a double quantum dot laterally defined in a GaAs/AlGaAs heterostructure. To characterize a phonon cavity we generate standing surface acoustic waves (SSAW) by driving the cavity defining interdigital transducers and image the SSAW using atomic force microscopy (AFM), which is able to resolve submicron wavelengths of the SSAW at a few GHz. Alternative techniques are discussed in a related contribution by N. Ashurbekov.
Here, we focus on the AFM cantilever deflection, which substantially overestimates the SSAW amplitude because the cantilever with an eigenfrequency in the kHz range is driven by energy transfer from the much faster oscillating surface. We demonstrate a method to nevertheless determine the actual SSAW amplitude by comparing the hystereses of force curve measurements with model predictions based on solving the equation of motion of the driven cantilever [1]. Finally we present our first characterization measurements of a double quantum dot coupled to a phonon cavity.
[1] J. Hellemann et al, PRApplied 17, 044024 (2022)