Few-Electron Quantum Dot Magnetospectroscopy Dependences on Tunable Coupling and Confinement

Magnetospectroscopy is a foundational technique for understanding quantum dots (QDs). It allows the extraction of important information including electron occupation, the lever arm to device gates, as well as the valley and orbital splittings. The complexity of silicon QD systems is increasing, allowing much greater tunability. However, the sensitivity of the QD valley and orbital behavior to the tuning parameters of these QD layouts is not well established. In this work, we measure the magnetospectroscopy of a lithographically-defined few-electron QD in silicon. We report on observed changes to the magnetospectroscopy as a function of QD lateral confinement and tunnel coupling to the reservoirs. The influence of the interaction between the main QD and a second neighboring dot is also investigated.

This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.