arXiv subjects

R. S. Whitney

Publications and source records attributed to R. S. Whitney.

2 recordsLinked to original sources

arXiv2022

Local bistability under microwave heating for spatially mapping disordered superconductors

We theoretically study a strongly disordered superconducting layer heated by near-field microwave radiation from a nanometric metallic tip. The microwaves heat up the quasiparticles, which cool by phonon emission and conduction away from the heated area. Due to a bistability with two stable states of the electron temperature under the tip, the heating can be tuned to induce a submicrometer-sized normal region bounded by a sharp domain wall between high- and low-temperature states. We propose this as a local probe to access different physics from existing methods, for example, to map out inhomogeneous superfluid flow in the layer. The bistability-induced domain wall can significantly improve its spatial resolution.

cond-mat.mes-hall↗

arXiv2009

Coherent Thermoelectric Effects in Mesoscopic Andreev Interferometers

We investigate thermoelectric transport through Andreev interferometers. We show that the ratio of the thermal and the charge conductance exhibits large oscillations with the phase difference $ϕ$ between the two superconducting contacts, and that the Wiedemann-Franz law holds only when $ϕ=π$. A large average thermopower furthermore emerges whenever there is an asymmetry in the dwell times to reach the superconducting contacts. When this is the case, the thermopower is odd in $ϕ$. In contrast, when the average times to reach either superconducting contact are the same, the average thermopower is zero, however mesoscopic effects (analogous to universal conductance fluctuations) lead to a sample-dependent thermopower which is systematically even in $ϕ$.

cond-mat.supr-con↗