Nonlocal measurement of quasiparticle charge and energy relaxation in proximitized semiconductor nanowires using quantum dots

Understand

The lowest-energy excitations of superconductors do not carry an electric charge, as their wave function is equally electron-like and hole-like.

• This fundamental property is not easy to study in electrical measurements that rely on the charge to generate an observable signal.
• The ability of a quantum dot to act as a charge filter enables us to solve this problem and measure the quasiparticle charge in superconducting-semiconducting hybrid nanowire heterostructures.
• We report measurements on a three-terminal circuit, in which an injection lead excites a non-equilibrium quasiparticle distribution in the hybrid system, and the electron or hole component of the resulting quasiparticles is detected using a quantum dot as a tunable charge and energy filter.