Vadim Khrapai | Searcharxiv

arXiv2023

Quantum Hall Bogoliubov Interferometer

A quantum Hall interferometer containing a grounded superconducting terminal is proposed. This geometry allows to control the Andreev and normal scattering amplitudes of sub-gap Bogoliubov quasiparticles with the Aharonov-Bohm phase, as well as with the constrictions defining the interferometer loop. The conductance matrix of such a three-terminal NSN interference device exhibits a much richer behavior as compared to its two-terminal Fabry-Pérot counterpart, which is illustrated by non-trivial behavior of non-local charge and heat responses. A single edge version of the interferometer enables full on-demand control of the electron-hole superposition, including resonant enhancement of arbitrary small Andreev reflection probability up to 1, and can be used as a building block in future more complex interference setups.

cond-mat.mes-hall↗

arXiv2020

Strategy for accurate thermal biasing at the nanoscale

We analyze the benefits and shortcomings of a thermal control in nanoscale electronic conductors by means of the contact heating scheme. Ideally, this straightforward approach allows one to apply a known thermal bias across nanostructures directly through metallic leads, avoiding conventional substrate intermediation. We show, by using the average noise thermometry and local noise sensing technique in InAs nanowire based devices, that a nanoscale metallic constriction on a SiO2 substrate acts like a diffusive conductor with negligible electron-phonon relaxation and non-ideal leads. The non-universal impact of the leads on the achieved thermal bias -- which depends on their dimensions, shape and material composition -- is hard to minimize, but is possible to accurately calibrate in a properly designed nano-device. Our results allow to reduce the issue of the thermal bias calibration to the knowledge of the heater resistance and pave the way for accurate thermoelectric or similar measurements at the nanoscale.

cond-mat.mes-hall↗