Demonstration of a hole quantum dot in Ge/SiGe

Heavy holes in Ge/SiGe quantum well heterostructures have potential advantages as spin-based qubits including all electrical control through intrinsic spin-orbit coupling, the possibility of isotopic enrichment, and the absence of valley states. Recently high-mobility material suitable to host spin qubits has become available. We will report on experiments which demonstrate the formation of a gate-controlled lateral quantum dot in undoped Ge/SiGe heterostructure quantum wells. Details of the device fabrication and low-temperature characterization of the quantum dot will be presented. These results, demonstrating confinement of holes in this material system, are the first step toward achieving heavy hole-based spin qubits in a lateral quantum dot device design in germanium. 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.