arXiv subjects

Leo Kouwenhoven

Publications and source records attributed to Leo Kouwenhoven.

3 recordsLinked to original sources

arXiv2024

Perspective on Majorana bound-states in hybrid superconductor-semiconductor nanowires

Topological quantum computing and Majorana bound states were initially theorized between 2000 and 2010. These concepts gradually transitioned to practical implementations during the subsequent decade (2010-2020). Various directions have been investigated with mixed success. With respect to hybrid superconductor-semiconductor devices, great progress has been achieved in the larger area of mesoscopic superconductivity. Firm evidence for a topological phase in hybrid 1D nanowires, however, has not been demonstrated. Now, in the third decade, the lack of definitive topological results prompts a reevaluation. As an active participant, I have witnessed phases of hope, exuberance, and a return to realism and taking a step back. This Perspective provides a personal account of the past decade, my view on the current situation and challenges ahead. I assume the reader is familiar with the subject at the level of, e.g. the review by Prada et al. [1] from which I repeat as little as possible and refer to the extensive reference list for a comprehensive overview. The purpose of this Perspective is to share personal experiences and motivations.

cond-mat.mes-hall↗

arXiv2012

Growth and optical properties of axial hybrid III-V/Si nanowires

Hybrid silicon nanowires with an integrated light-emitting segment can significantly advance nanoelectronics and nanophotonics. They would combine transport and optical characteristics in a nanoscale device, which can operate in the fundamental single-electron and single-photon regime. III-V materials, such as direct bandgap gallium-arsenide, are excellent candidates for such optical segments. However, interfacing them with silicon during crystal growth is a major challenge, because of the lattice mismatch, different expansion coefficients and the formation of anti-phase boundaries. Here, we demonstrate a silicon nanowire with an integrated gallium-arsenide segment. We precisely control the catalyst composition and surface chemistry to obtain dislocation-free interfaces. The integration of gallium-arsenide of high optical quality with silicon is enabled by short gallium phosphide buffers. We anticipate that such hybrid silicon/III-V nanowires open practical routes for quantum information devices, where for instance electronic and photonic quantum bits are manipulated in a III-V segment and stored in a silicon section.

cond-mat.mtrl-sci↗

arXiv2001

Revival of the Kondo effect

This is a popular review of some recent investigations of the Kondo effect in a variety of mesoscopic systems. After a brief introduction, experiments are described where a scanning tunneling microscope measures the surroundings of a magnetic impurity on a metal surface. In another set of experiments, Kondo effect creates a number of characteristic features in the electron transport through small electronic devices -- semiconductor quantum dots or single-molecule transistors which can be tuned by applying appropriate gate voltages. The article contains 5 color figures, photo of Jun Kondo, but no equations.

cond-mat.mes-hall↗