Hybrid superconductor-semiconductor devices made from self-assembled SiGe nanocrystals on silicon

Abstract

The epitaxial growth of germanium on silicon leads to the self-assembly of SiGe nanocrystals via a process that allows the size, composition and position of the nanocrystals to be controlled. This level of control, combined with an inherent compatibility with silicon technology, could prove useful in nanoelectronic applications. Here we report the confinement of holes in quantum-dot devices made by directly contacting individual SiGe nanocrystals with aluminium electrodes, and the production of hybrid superconductorsemiconductor devices, such as resonant supercurrent transistors, when the dot is strongly coupled to the electrodes. Charge transport measurements on weakly coupled quantum dots reveal discrete energy spectra, with the confined hole states displaying anisotropic gyromagnetic factors and strong spin-orbit coupling strength with pronounced gate-voltage and magnetic-field dependence.

35 pages, 6 figures

References in corpus (12)

• Coherent control of a single electron spin with electric fields
• Supercurrent reversal in quantum dots
• Quantum supercurrent transistors in carbon nanotubes
• Quantum phase transition in a single-molecule quantum dot
• Direct Measurement of the Spin-Orbit Interaction in a Two-Electron InAs Nanowire Quantum Dot
• Electric-field controlled spin reversal in a quantum dot with ferromagnetic contacts
• Kondo Universal Scaling for a Quantum Dot Coupled to Superconducting Leads
• Ballistic Spin Resonance
• Kondo effect in a semiconductor quantum dot coupled to ferromagnetic electrodes
• Spin relaxation at the singlet-triplet crossing in a quantum dot
• Superconductivity-enhanced bias spectroscopy in carbon nanotube quantum dots
• Lifetime measurements (T1) of electron spins in Si/SiGe quantum dots

Cited by in corpus (6)

• Prospects for Spin-Based Quantum Computing
• Tunable g factor and phonon-mediated hole spin relaxation in Ge/Si nanowire quantum dots
• Interplay of Coulomb interaction and spin-orbit effects in multi-level quantum dots
• Hybrid high-temperature superconductor-semiconductor tunnel diode
• Quantum dot spectroscopy of proximity-induced superconductivity in a two-dimensional electron gas
• Finite-bias conductance anomalies at a singlet-triplet crossing