"Superconductivity in Diamond"

Datum

05.07.2016

Zeit

11:00 - 13:00

Sprecher

Dr. Gufei Zhang

Zugehörigkeit

INPAC-Institute for Nanoscale Physics and Chemistry

Sprache

en

Hauptthema

Materialien

Andere Themen

Physik, Materialien

Host

Dr. Michael Nicklas

Beschreibung

Superconductivity, or infinite conductivity, appears as a result of formation of quantum condensate of Cooper pairs making possible a dissipationless flow of charged bosons. At first sight, superconductivity should be provided by well established conducting state, but in reality the best conductors (Ag, Au) do not super-conduct at all, while, instead, superconductivity gains a lot from being situated in the vicinity of the insulator-metal transition induced by doping, e.g., doped copper oxides and iron pnictides. Naturally, one cannot help asking why good superconductivity appears in a bad conductor. Another interesting puzzle, under practical concerns and related to the origin of superconductivity, is the role of disorder. How does superconductivity work in the case that the quantum condensate of Cooper pairs is perturbed by disorder on different length scales? Boron-doped granular diamond provides the community a powerful stage for answering the questions mentioned above. Firstly, there is a common ground between boron-doped diamond and high Tc superconductors, i.e., they are both doped insulators, while the relatively low Tc of the former becomes an advantage when high magnetic fields are infeasible for relevant investigations under normal experimental conditions. Secondly, due to the unique growth mode, synthetic diamonds mostly have a granular morphology, which makes the system disordered on different length scales, together with the doping-induced structural imperfections. This contribution will provide an overview of the superconductivity in diamond, based on the research results obtained at INPAC – KU Leuven. The granular nature of the superconductivity in diamond will be interpreted by showing the electrical transport properties, the magnetic properties and the local direct measurement results of the system. Our experimental results also show that even deep on the metallic side of the insulator-metal transition, boron-doped diamond (a three-dimensional system) still demonstrate anomalous and interesting physical properties as a result of quantum confinement and coherence effects in the presence of granular disorder.

Links

• MPI CPfS

Letztmalig verändert: 04.07.2016, 09:42:19