Simulating scanning tunneling microscope measurements

Abstract

One of the largest problems in scanning tunneling microscopy design is noise control. It is the burden of the designer to determine if money should be used to build a floating room for vibration isolation or for top-of-the-line preamplifiers that can be placed at low temperatures. This thesis presents a simulation of the STM measurement chain, from tunneling tip to computer control. The goal is to see how noise at different stages of the measurement chain affect the output of spectroscopy (density of states) measurements. Specifically, we look at how spectroscopy measurements depend on the temperature of the sample, the density of states in the sample and tip, the shakiness of the tip, the noise present in the current preamplifier, and several other settings. Chapter 1 describes STM spectroscopy measurement, Chapter 2 explains how it is simulated, and Chapter 3 finally looks at the results of various simulations.