Measurements of flux dependent screening in Aharonov-Bohm rings

TL;DR

This study measures flux-dependent polarizability in mesoscopic rings to explore how electronic phase coherence influences screening, revealing flux oscillations and enhanced screening when time reversal symmetry is broken.

Contribution

It provides experimental evidence of flux-dependent screening effects in mesoscopic rings, confirming recent theoretical predictions and analyzing the influence of density and temperature.

Findings

Flux oscillations with half flux quantum period observed

Positive magneto-polarizability indicates enhanced screening

Effect depends on electronic density and temperature

Abstract

In order to investigate the effect of electronic phase coherence on screening we have measured the flux dependent polarizability of isolated mesoscopic rings at 350 MHz. At low temperature (below 100 mK) both non-dissipative and dissipative parts of the polarizability exhibit flux oscillations with a period of half a flux quantum in a ring. The sign and amplitude of the effect are in good agreement with recent theoretical predictions. The observed positive magneto-polarizability corresponds to an enhancement of screening when time reversal symmetry is broken. The effect of electronic density and temperature are also measured.