Freek Massee
     Laboratoire de Physique des Solides, CNRS
shot-noise compatible STM headShot-noise compatible STM head.

Shot-noise scanning tunneling microscopy

In a tunnel junction, the power of the current fluctuations, SI, is linear with the tunneling current, where the current noise is called shot-noise (SN). In a non-interacting system, the shot-noise is Poissonian as each electron crossing the tunnel barrier is independent from the others. As soon as the electrons in one of the terminals (i.e. the tip or the sample in the case of STM) are interacting with one another, the shot-noise will be directly affected. In addition to addressing dynamics, shot-noise also allows for directly measuring the charge locally as the shot-noise power spectrum is proportional to the charge transferred. Currently, I am setting up a shot-noise compatible scanning tunneling microscope at the Laboratoire de Physique des Solides to measure the dynamics at the atomic scale of correlated electron systems. For more details on 'traditional' scanning tunneling microscopy click here.