Feedback loop dependent charge density wave imaging by scanning tunneling spectroscopy

This is the authors' abstract. We don't add key points for this paper.

Scanning tunneling spectroscopy (STS) maps can be influenced by the so-called set point effect. This effect is often considered negligible, allowing various imaging modes to be used interchangeably without significant concern for subtle differences. However, this assumption may not always hold true. In this study, the authors examine how the inversion of STS imaging contrast of a charge density wave (CDW) varies across different imaging methods in 1T-TiSe₂, a model CDW system with a CDW gap not centered at the Fermi level, which accentuates the set point effect. The findings reveal that only constant-height imaging enables a reliable detection of the charge density wave gap, effectively suppressing the additional contrast inversions observed with other methods.