Marcel Meyer

Spin qubits made from gate defined quantum dots are attractive candidates for scaling quantum computation because of their small footprint and compatibility with semiconductor manufacturing. However, currently large inherent variations of the local potential hinder the implementation of advanced design proposals relying on shared gate control. Here, we present a method to electrically tune the uniformity of the potential landscape in silicon and germanium quantum dot devices. By harvesting the hysteretic nature of gate voltage-current characteristics of individual gates we tune their pinch-off voltages and thus the potential beneath them. We show that after this tuning the new state remains stable for several hours and apply our findings to unify the pinch-off voltages of the plunger gates in a linear four-dot array. Our work highlights a new tuning knob for spin qubits that can ease the operation of state of the art devices and offers new perspectives for material characterization and the scaling of spin qubits.