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Physics


In 2014, I received a PhD in Theoretical Physics (Condensed Matter Theory and Quantum Computing) at the University of Basel with the predicate "Summa Cum Laude", under the supervision of Prof. Dr. Daniel Loss.


The main result of my thesis is the discovery of a novel spin-orbit interaction (SOI) of Rashba type that arises for holes in semiconducting nanowires in the presence of an electric field. In contrast to conventional Rashba and Dresselhaus SOI, this so-called direct Rashba SOI (sometimes also Kloeffel-Trif-Loss SOI) is not suppressed by the fundamental band gap of the semiconductor and therefore unusually strong. The direct Rashba SOI provides high external control and can be of great use, e.g., in spintronics and for the implementation of spin-based quantum computers.


Besides theoretical physics I also gained experience in experimental physics. In particular, I performed experiments in the nanophotonics group of Prof. Dr. Richard Warburton (results published in Physical Review Letters) and in the biophotonics group of Dr. Lynn Paterson (Masters project on in-vivo measurement of the refractive index of single biological cells).


Currently, I analyze theoretically the properties of various novel heterostructures, with particular focus on spin states therein.



Publications



  1. Strong Spin-Orbit Interaction, Helical Hole States, and Spin Qubits in Nanowires and Quantum Dots
    C. Kloeffel
    PhD Thesis, Basel, 2014
  2. Acoustic Phonons and Strain in Core/Shell Nanowires
    C. Kloeffel, M. Trif, and D. Loss
    Phys. Rev. B 90, 115419 (2014)
  3. Phonon-Mediated Decay of Singlet-Triplet Qubits in Double Quantum Dots
    V. Kornich, C. Kloeffel, and D. Loss
    Phys. Rev. B 89, 085410 (2014)
  4. Circuit QED with Hole-Spin Qubits in Ge/Si Nanowire Quantum Dots
    C. Kloeffel, M. Trif, P. Stano, and D. Loss
    Phys. Rev. B 88, 241405(R) (2013)
  5. Tunable g Factor and Phonon-Mediated Hole Spin Relaxation in Ge/Si Nanowire Quantum Dots
    F. Maier, C. Kloeffel, and D. Loss
    Phys. Rev. B 87, 161305(R) (2013)
  6. Prospects for Spin-Based Quantum Computing in Quantum Dots
    C. Kloeffel and D. Loss
    Annu. Rev. Condens. Matter Phys. 4, 51 (2013)
  7. Strong Spin-Orbit Interaction and Helical Hole States in Ge/Si Nanowires
    C. Kloeffel, M. Trif, and D. Loss
    Phys. Rev. B 84, 195314 (2011)
  8. Controlling the Interaction of Electron and Nuclear Spins in a Tunnel-Coupled Quantum Dot
    C. Kloeffel, P. A. Dalgarno, B. Urbaszek, B. D. Gerardot, D. Brunner, P. M. Petroff, D. Loss, and R. J. Warburton
    Phys. Rev. Lett. 106, 046802 (2011)


Conferences and scientific visits



Talks and poster presentations, participation in schools and conferences, visits in other research groups, and project review meetings in Austria, Belgium, Denmark, England, France, Germany, Italy, Japan, Netherlands, Scotland, Switzerland, USA.



Other activities



Member of excellent and well-funded research projects such as the NCCR QSIT and SiSPIN.


Referee for Science Magazine, Nature Nanotechnology, Physical Review X, Physical Review B, Nanoscale Research Letters, Europhysics Letters, …


Teaching assistant for lectures on nanophysics, quantum mechanics, relativistic quantum field theory, electrodynamics, optics, …


Webmaster of the Departement of Physics of the University of Basel and the International School and Conference SpinTech VIII.


Founding member of the club Multilingual Toastmasters of the University of Basel.