Ion implanted Si:P double dot with gate tunable interdot coupling

We report on milli-Kelvin charge sensing measurements of a silicon double-dot system fabricated by phosphorus ion implantation. An aluminum single-electron transistor is capacitively coupled to each of the implanted dots enabling the charging behavior of the double-dot system to be studied independent of current transport. Using an electrostatic gate, the interdot coupling can be tuned from weak to strong coupling. In the weak interdot coupling regime, the system exhibits well-defined double-dot charging behavior. By contrast, in the strong interdot coupling regime, the system behaves as a single dot.