Thursday, January 2, 2014
Applied Physics Seminar
Spin Transport and Majorana Fermions: Exploiting Spin-Orbit Coupling in Semiconductor Nanowires and Topological Insulators
Vlad Pribiag, Postdoctoral Fellow, Kavli Institute of Nanoscience, Delft University of Technology
Vlad S. Pribiag
Kavli Institute of Nanoscience Delft, Delft University of Technology
Conventional semiconductors with strong spin-orbit coupling and topological insulators have emerged as promising platforms for spintronics and quantum information processing. In the first part of this talk, I will present experiments relying on the strong spin-orbit interaction in InSb nanowires to demonstrate all-electrical control of individual spins in quantum dots. These experiments highlight the potential of electric dipole spin resonance (EDSR) as both a means for controlling spin-based qubits and as a powerful spectroscopic tool for electrons and holes. Holes, in particular, are very attractive for quantum information processing due to the possibility of longer spin coherence and stronger spin-orbit coupling than electrons, both consequences of the p-orbital symmetry of the Bloch wavefunction. Our work demonstrates that hole-spin states can be manipulated and probed in a transport experiment, providing a path for the implementation of hole-spin based spintronic and opto-electronic devices. The second part of the talk focuses on our current efforts to develop 2D topological insulators (2D TIs) into an experimental platform for Majorana zero modes. These exotic fermionic excitations are predicted to have non-Abelian statistics, making them ideal candidates for fault-tolerant quantum computation. I will discuss superconducting junctions based on InAs/GaSb double quantum wells as a first step towards Majorana experiments based on this gate-tunable 2D TI.