Closed-loop-based observer approach for tunneling current parameter estimation in an experimental STM

Abstract

This paper is about parameter estimation in quantum effect of tunneling current, and is based on an experimental device of Scanning Tunneling Microscope (STM) type. Since this effect needs feedback control in order to be obtained and kept, a closed-loop stability analysis is first presented prior to any estimation. Then, in this context of closed-loop operation, an observer approach is proposed to estimate the couple of parameters which characterize the tunneling current (nonlinear) model. An extension of this observer technique to topography estimation is also discussed, and all the methodologies are illustrated with experimental data.