Measuring the Kondo Cloud by Current Cross Correlations in Helical Liquids

Abstract

The Kondo cloud, represented by the correlations between the magnetic moment and the spin density in the leads of a Kondo setup, is until now eluding its observation. We exploit the unique coupling of spin and direction of motion of the recently discovered helical liquids in a setup with two leads to establish a proportionality between the Kondo cloud and the time resolved current cross correlations. This relation holds around a specific choice of model parameters. Thereby, we provide a new and direct way to detect the Kondo cloud.