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A most fundamental and longstanding goal in spintronics is to electrically tune highly efficient spin injectors and detectors, preferably compatible with nanoscale electronics. Here, we demonstrate all these points using semiconductor…
We explore the signatures of Majorana fermions in a nanowire based topological superconductor-quantum dot-topological superconductor hybrid device by charge transport measurements. The device is made from an epitaxially grown InSb nanowire…
Interfacing s-wave superconductors and quantum spin Hall edges produces time-reversal-invariant topological superconductivity of a type that can not arise in strictly 1D systems. With the aim of establishing sharp fingerprints of this novel…
Nanowires with a GaSb core and an InAs shell (and the inverted structure) are interesting for studies of electron-hole hybridization and interaction effects due to the bulk broken band-gap alignment at the material interface. We have used…
Cryogenic scanning tunneling microscopy was employed in combination with density-functional theory calculations to explore quantum dots made of In adatoms on the InAs(110) surface. Each adatom adsorbs at a surface site coordinated by one…
Quantum annealing is an optimization technique which potentially leverages quantum tunneling to enhance computational performance. Existing quantum annealers use superconducting flux qubits with short coherence times, limited primarily by…
We present a computational study of the adhesive and structural properties of the Al/Al2O3 interfaces as building blocks of the Metal-Insulator-Metal (MIM) tunnel devices, where electron transport is accomplished via tunnelling mechanism…
We create laterally large and low disorder quantum well based quantum dots to study single electron additions to two dimensional electron systems (2DES). Electrons tunnel into these dots across an AlGaAs tunnel barrier from a single $n+$…
The thermoelectric properties of quantum dot arrays (QDAs) embedded in nanowires connected to electrodes are studied theoretically in the Coulomb blockade regime. A Hurbbard-Anderson model is used to simulate the electronic contribution to…
A Cooper pair splitter consists of a central superconducting contact, S, from which electrons are injected into two parallel, spatially separated quantum dots (QDs). This geometry and electron interactions can lead to correlated electrical…
Coupled electron spins in semiconductor double quantum dots hold promise as the basis for solid-state qubits. To date, most experiments have used III-V materials, in which coherence is limited by hyperfine interactions. Ge/Si…
This work presents an analysis of the electronic and optical properties of InAs/GaAs columnar quantum dots (QDs) by performing multi-million-atom tight-binding simulations. The plots of the polarisation-dependent ground state optical…
Semiconductor quantum dots (QDs) offer a platform to explore the physics of quantum electronics including spins. Electron spins in QDs are considered good candidates for quantum bits in quantum information processing, and spin control and…
Generating and detecting radiation in the technologically relevant range of the so-called terahertz gap ($0.1 - 10$ THz) is challenging because of a lack of efficient sources and detectors. Quantum dots in carbon nanotubes have shown great…
Electrons in closed systems can exhibit Coulomb blockade (CB) oscillations due to charge quantization. Here, we report CB oscillations in aluminum superconducting islands on InAs nanowires in the open regime. The Al island is connected to…
Using atomistic pseudopotential and configuration-interaction many-body calculations, we predict a metal-nonmetal transition and an excitonic ground state in the InAs/InSb quantum dot (QD) system. For large dots, the conduction band minimum…
We propose and demonstrate wide-band capacitance measurements on a semiconductor double-quantum dot (DQD) to study tunneling dynamics. By applying phase-tunable high-frequency signals independently to the DQD and a nearby…
Resonant tunneling through identical potential barriers is a textbook problem in quantum mechanics. Its solution yields total transparency (100% tunneling) at discrete energies. This dramatic phenomenon results from coherent interference…
We study low-temperature transport through carbon nanotube quantum dots in the Coulomb blockade regime coupled to niobium-based superconducting leads. We observe pronounced conductance peaks at finite source-drain bias, which we ascribe to…
Atom manipulation by scanning tunneling microscopy was used to construct quantum dots on the InAs(111)A surface. Each dot comprised six ionized indium adatoms. The positively charged adatoms create a confining potential acting on…