experimental condensed matter physics; nuclear demagnetization cooling; quantum wires; semiconductor spins; spin qubits; nanophysics; ultralow temperature physics; edge states and topological insulators
Weigele Pirmin J., Marinescu D. C., Dettwiler Florian, Fu Jiyong, Mack Shawn, Egues J. Carlos, Awschalom David D., Zumbühl Dominik M. (2020), Symmetry breaking of the persistent spin helix in quantum transport, in Physical Review B
, 101(3), 035414-035414.
Lennon D. T., Moon H., Camenzind L. C., Yu Liuqi, Zumbühl D. M., Briggs G. A .D., Osborne M. A., Laird E. A., Ares N. (2019), Efficiently measuring a quantum device using machine learning, in npj Quantum Information
, 5(1), 79-79.
Rehmann Mirko K., Kalyoncu Yemliha B., Kisiel Marcin, Pascher Nikola, Giessibl Franz J., Müller Fabian, Watanabe Kenji, Taniguchi Takashi, Meyer Ernst, Liu Ming-Hao, Zumbühl Dominik M. (2019), Characterization of hydrogen plasma defined graphene edges, in Carbon
, 150, 417-424.
Camenzind Leon C., Yu Liuqi, Stano Peter, Zimmerman Jeramy D., Gossard Arthur C., Loss Daniel, Zumbühl Dominik M. (2019), Spectroscopy of Quantum Dot Orbitals with In-Plane Magnetic Fields, in Physical Review Letters
, 122(20), 207701-207701.
Marinescu D. C., Weigele Pirmin J., Zumbühl Dominik M., Egues J. Carlos (2019), Closed-Form Weak Localization Magnetoconductivity in Quantum Wells with Arbitrary Rashba and Dresselhaus Spin-Orbit Interactions, in Physical Review Letters
, 122(15), 156601-156601.
Stano Peter, Hsu Chen-Hsuan, Camenzind Leon C., Yu Liuqi, Zumbühl Dominik, Loss Daniel (2019), Orbital effects of a strong in-plane magnetic field on a gate-defined quantum dot, in Physical Review B
, 99(8), 085308-085308.
Camenzind Leon C., Yu Liuqi, Stano Peter, Zimmerman Jeramy D., Gossard Arthur C., Loss Daniel, Zumbühl Dominik M. (2018), Hyperfine-phonon spin relaxation in a single-electron GaAs quantum dot, in Nature Communications
, 9(1), 3454-3454.
Patlatiuk T., Scheller C. P., Hill D., Tserkovnyak Y., Barak G., Yacoby A., Pfeiffer L. N., West K. W., Zumbühl D. M. (2018), Evolution of the quantum Hall bulk spectrum into chiral edge states, in Nature Communications
, 9(1), 3692-3692.
Stano Peter, Hsu Chen-Hsuan, Serina Marcel, Camenzind Leon C., Zumbühl Dominik M., Loss Daniel (2018), g -factor of electrons in gate-defined quantum dots in a strong in-plane magnetic field, in Physical Review B
, 98(19), 195314-195314.
Kuhlmann Andreas V., Deshpande Veeresh, Camenzind Leon C., Zumbühl Dominik M., Fuhrer Andreas (2018), Ambipolar quantum dots in undoped silicon fin field-effect transistors, in Applied Physics Letters
, 113(12), 122107-122107.
Froning F. N. M., Rehmann M. K., Ridderbos J., Brauns M., Zwanenburg F. A., Li A., Bakkers E. P. A. M., Zumbühl D. M., Braakman F. R. (2018), Single, double, and triple quantum dots in Ge/Si nanowires, in Applied Physics Letters
, 113(7), 073102-073102.
Friedl Martin, Cerveny Kris, Weigele Pirmin, Tütüncüoglu Gozde, Martí-Sánchez Sara, Huang Chunyi, Patlatiuk Taras, Potts Heidi, Sun Zhiyuan, Hill Megan O., Güniat Lucas, Kim Wonjong, Zamani Mahdi, Dubrovskii Vladimir G., Arbiol Jordi, Lauhon Lincoln J., Zumbühl Dominik M., Fontcuberta i Morral Anna (2018), Template-Assisted Scalable Nanowire Networks, in Nano Letters
, 18(4), 2666-2671.
This proposal describes work on three related projects, outlined below: microkelvin nanoelectronics, tunneling spectroscopy in quantum wires, and spin qubits.Ultralow temperatures below 1 mK in electronic transport experiments can open the door to novel quantum states of matter and boost quantum coherence e.g. in qubits or Majorana devices. Over the past years, our group in Basel has developed a new technique of cooling nanoelectronic devices to ultralow temperatures: we have adapted the well established technique of adiabatic nuclear demagnetization to the specific needs of quantum transport experiments. We have recently demonstrated 150 microK in the nuclear refrigerators, and currently hold the records for the lowest temperatures in both tunnel junction thermometers as well as Coulomb blockade thermometers. After years of efforts, breaking of the 1 mK barrier is imminent, and in this proposal, we are describing our proposed routes down to 1 mK and below. In recent experiments, we have used cleaved edge overgrowth GaAs quantum wires to develop momentum-resolved tunneling spectroscopy. This allows us to probe the evolution of the chiral quantum Hall edge states with unprecedented resolution down to 1 nm, ranging from very low magnetic fields all the way to high fields where depopulation occurs. In this proposal, we will employ and modify the tunneling spectroscopy to probe a broad range of fascinating effects including fractional quantum Hall states, exchange enhanced spin splitting and edge state separation, edge state reconstruction upon depopulation, and Fermi level pinning. Finally, this technique could be modified slightly to be useful to study edge states in other materials such as graphene or transition metal dichalcogenides, or for the study of quantum wires themselves. Finally, we propose to study spin qubits in Ge/Si quantum wires and gate defined GaAs quantum dots. With the piezo-electric rotator which is operating in our cryostat, numerous new possibilities are opening up for applying strong magnetic fields up to 14 T in any direction in a 2D plane. Using our advance spectroscopy methods, we will measure the g-factor anisotropy and spin tunneling asymmetry, and compare it to model predictions. Much larger Rabi frequencies than before are expected when using an optimized spin-orbit configuration, which we will test in experiments. In Ge/Si qubits, we propose the a path from forming repeatable gate defined quantum dots in these wires, to electrical control of the very strong SO coupling. The strength of this SO coupling can be tuned using side gates. Finally, we propose electric-dipole spin resonance experiments in these wires, which are predicted to give very fast Rabi frequencies.