Phase Analysis of Charge Density Waves in Kagome Superconductors Using Scanning Tunneling Microscopy*

Charge density waves (CDWs) can be analyzed using Scanning Tunneling Microscope (STM) images. In this study, we demonstrate an approach to investigate CDWs by registering STM images of the same sample at different bias voltages, followed by an Inverse Fourier Transform and line cuts of the resulting images. This process allowed us to create a waterfall plot, revealing the phase shift in the charge density wave. The phase shift provided crucial insights into positioning the Charge Density Wave gap relative to the Fermi Level. Our investigation focused on a sample of crystal CsV3Sb5, and we discovered that the pi phase shift occurs between unexpected sample biases of -280 meV and -240 me instead of at the expected 0 meV.