High-precision atomic imaging using an innovative vibration-isolated scanning tunneling microscope

Abstract

The stability of the scanning unit in a scanning tunneling microscope (STM) is essential for achieving high-resolution imaging. In this study, we present a non-metallic STM with a mechanically isolated scanning unit, ensuring long-term drift stability, low backlash, and high repeatability. By decoupling the piezoelectric scanning tube (PST) from the piezoelectric motor tube (PMT), the design effectively minimizes motor-induced instabilities and vibrations, significantly improving STM performance. The use of non-metallic materials for key components prevents eddy current interference and ensures long-term reliability. A sapphire-based frame provides high stiffness and compactness, with an eigenfrequency of 16.2 kHz in bending mode, reducing vibration noise during atomic imaging. The system exhibits excellent stability, maintaining low drift rates in both the X-Y plane and Z direction, ensuring precise tip-sample alignment. The performance of the home-built STM was validated through high-resolution atomic imaging of graphite and TaS₂ surfaces. The simple, compact, and high-precision stepping mechanism, along with its ability to operate at low voltage, reduces experimental complexity. These features facilitate advanced material studies in constrained environments, such as high magnetic fields and low temperatures.