Dephasing due to semi-conductor charging masks decoherence in electron-wall systems

Abstract

In the interaction between a quantum mechanical electron wave and a wall, loss of interference contrast is observed. It is of general interest to identify the mechanism and categorize its nature as dephasing or decoherence. Decoherence is of fundamental importance for the transition between the classical and quantum boundary, while dephasing is often an experimental detriment that needs to be understood and overcome. We find that the loss of contrast is attributed to a local charge distribution induced by secondary emission: a dephasing mechanism. This mechanism is expected to be present for many materials, is clearly visible for copper oxide, and can mask decoherence mechanisms. The local charge distribution on the wall causes a loss of contrast and electron beam deformation. A model based on Coulomb interaction with the surface charge gives good agreement for both features. Our model can thus be used to improve the experimental design and lead to separate out decoherence phenomena in the electron-wall system.