Kavli Affiliate: Menno Veldhorst
| First 5 Authors: Lazar Lakic, William I. L. Lawrie, David van Driel, Lucas E. A. Stehouwer, Yao Su
| Summary:
Planar germanium quantum wells have recently been shown to host hard-gapped
superconductivity. Additionally, quantum dot spin qubits in germanium are
well-suited for quantum information processing, with isotopic purification to a
nuclear spin-free material expected to yield long coherence times. Therefore,
as one of the few group IV materials with the potential to host
superconductor-semiconductor hybrid devices, proximitized quantum dots in
germanium is a compelling platform to achieve and combine topological
superconductivity with existing and novel qubit modalities. Here we demonstrate
a quantum dot (QD) in a Ge/SiGe heterostructure proximitized by a platinum
germanosilicide (PtGeSi) superconducting lead (SC), forming a SC-QD-SC
junction. We show tunability of the QD-SC coupling strength, as well as gate
control of the ratio of charging energy and the induced gap. We further exploit
this tunability by exhibiting control of the ground state of the system between
even and odd parity. Furthermore, we characterize the critical magnetic field
strengths, finding a critical out-of-plane field of 0.90(4). Finally we explore
sub-gap spin splitting in the device, observing rich physics in the resulting
spectra, that we model using a zero-bandwidth model in the Yu-Shiba-Rusinov
limit. The demonstration of controllable proximitization at the nanoscale of a
germanium quantum dot opens up the physics of novel spin and superconducting
qubits, and Josephson junction arrays in a group IV material.
| Search Query: ArXiv Query: search_query=au:”Menno Veldhorst”&id_list=&start=0&max_results=3