Kalman Filter Based Estimation of Surface Conductivity in STM

In scanning tunneling microscopy (STM), the surface conductivity,
$\sigma$
, contributes to the total tunneling current due to a quantum phenomenon. The surface conductivity may change from atom to atom during a scan. It is an important electronic property of the surface that cannot be directly measured with current spectroscopy methods. In this paper, we propose an offline estimation method based on augmented state Kalman filter to determine
$\sigma$
. We demonstrate the successful application of this method to a set of STM images obtained from a Si
$(100)-2\times 1:\mathrm{H}$
passivated surface.