University of Basel

Department
of Physics

Quantum Coherence Lab - Zumbühl Group

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European Microkelvin Platform (EMP) launched today in Heidelberg

Kick-off meeting of the European Microkelvin Platform (EMP), a new advanced EU research infrastructure within H2020 launching today in Heidelberg! 8 access giving laboratories with 9 partners from academia and industry from across Europe!…
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Dr. Mohammad Samani joins our group as a postdoc

Having received his PhD from the University of British Columbia, Canada, in Prof. Joshua Folk's group on "Local probe of electronic states in high mobility quantum Hall samples", Mohammad is starting on his postdoc on the microkelvin…
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PhD defense of Bilal Kalyoncu

Yemliha "Bilal" Kalyoncu successfully defended his PhD thesis "Hydrogen Plasma Etched Graphene Nanoribbons" today with Dr. Jonathan Prance, Lancaster University, as coreferee and Prof. Ilaria Zardo chairing. Congratulations, Bilal, on a…
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Miguel J. Carballido joins our group as a PhD student

Having received his MSc in Physics from the University of Basel on the thermal conductivity of nanowires using Ramanthermometry in Prof. Ilaria Zardo's group, Miguel is starting his PhD thesis on the Ge/Si nanowire project, developing these…
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New on arXiv: Closed-form weak localization with arbitrary Rashba and Dresselhaus interactions

We derive a closed-form expression for the weak localization corrections to the magnetoconductivity of a 2D electron system with arbitrary Rashba and both linear and cubic Dresselhaus spin-orbit interactions in a perpendicular magnetic…
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New ArXiv submission: Effciently measuring a quantum device using machine learning

Tuning quantum devices is becoming time-consuming as systems are scaled up, e.g. to numerous gates or contacts, and will soon become intractable without automation. Here, we present measurements on a quantum dot done by a machine learning…
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"Ambipolar dots in Si finFETs..." published in Appl. Phys. Letters

Ambipolar quantum dots in silicon fin fi eld-eff ect transistors are defined using exclusively standard complementary metal-oxide-semiconductor fabrication techniques. We demonstrate stable quantum dot operation in the few charge carrier…
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"Evolution of the Quantum Hall bulk spectrum" published in Nature Communications!

Using a GaAs cleaved-edge quantum wire, we perform spectroscopy revealing the momentum and position of the quantum Hall edge states with unprecedented precision. We present models in excellent agreement with the experiment—thus providing…
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"Hyperfine-phonon spin relaxation" published in Nature Communications!

Understanding and control of the spin relaxation time T1 is a key challenge for spin qubits, setting the fundamental upper limit to the qubit coherence and readout fidelity. We establish the prediction of hyperfine-phonon spin relaxation…
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Pulished in Appl. Phys. Letters: Ge/Si quantum dots

Published online on Aug 15 in Applied Physics Letters, our paper on gate defined quantum dots in Ge/Si nanowires, with single, double and triple dots, Pauli spin blockade, and signatures of a single hole quantum dot. Appl. Phys. Lett. 113,…
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Spin-orbit and g-factor effects in gate define quantum dots

We analyze orbital effects of an in-plane magnetic field on the spin structure of states of a gated quantum dot. Starting with a k.p Hamiltonian, we perturbatively calculate these effects for the conduction band of GaAs. We quantify…
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Ambipolar quantum dots in undoped silicon fin field-effect transistors: new arXiv submission

We integrate ambipolar quantum dots in silicon fin fi eld-eff ect transistors using exclusively standard complementary metal-oxide-semiconductor fabrication techniques. We realize ambipolarity by using a metallic nickel silicide with Fermi…
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Open Positions

We are looking for motivated and talented physicists for diverse projects. Please head over to the positions page for further information on the various projects.
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Single, double, and triple quantum dots in Ge/Si nanowires: new arXiv submission

We report highly tunable control of holes in Ge/Si core/shell nanowires (NWs). We demonstratethe a bility to create single quantum dots (QDs) of various sizes, with low hole occupation numbers and clearly observable excited states. For the…
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Two new manuscripts on arXiv, on Quantum-Dot Orbital-Spectroscopy with In-Plane Magnetic Fields!

Semiconductor spin qubits are leading candidates for quantum computation. Despite impressive progress over two decades, a tool to characterize the orbitals hosting the spin is lacking. Here, we demonstrate a spectroscopy method for quasi-2D…
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