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arXiv · 1606.00851

Extracting inter-dot tunnel couplings between few donor quantum dots in silicon

Samuel K. Gorman·Matthew A. Broome·Joris G. Keizer·Thomas F. Watson·Samuel J. Hile·William J. Baker·Michelle Y. Simmons
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Abstract

The long term scaling prospects for solid-state quantum computing architectures relies heavily on the ability to simply and reliably measure and control the coherent electron interaction strength, known as the tunnel coupling, $t_c$. Here, we describe a method to extract the $t_c$ between two quantum dots (QDs) utilising their different tunnel rates to a reservoir. We demonstrate the technique on a few donor triple QD tunnel coupled to a nearby single-electron transistor (SET) in silicon. The device was patterned using scanning tunneling microscopy-hydrogen lithography allowing for a direct measurement of the tunnel coupling for a given inter-dot distance. We extract ${t}_{\rm{c}}=5.5\pm 1.8\;{\rm{GHz}}$ and ${t}_{\rm{c}}=2.2\pm 1.3\;{\rm{GHz}}$ between each of the nearest-neighbour QDs which are separated by 14.5 nm and 14.0 nm, respectively. The technique allows for an accurate measurement of $t_c$ for nanoscale devices even when it is smaller than the electron temperature and is an ideal characterisation tool for multi-dot systems with a charge sensor.

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Samuel K. Gorman, Matthew A. Broome, Joris G. Keizer, Thomas F. Watson, Samuel J. Hile, William J. Baker, Michelle Y. Simmons. 2016-06-06. Extracting inter-dot tunnel couplings between few donor quantum dots in silicon. https://doi.org/10.1088/1367-2630%2F18%2F5%2F053041

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