Feedback loop dependent charge density wave imaging by scanning tunneling spectroscopy

Abstract

Scanning Tunneling Spectroscopy (STS) is a unique technique to probe the local density of states (LDOS) at the atomic scale by measuring the tunneling conductance between a sharp tip and a sample surface. However, the technique suffers of well-known limitations, the so-called set-point effect, which can potentially introduce artifacts in the measurements. We compare several STS imaging schemes applied to the LDOS modulations of the charge density wave state on atomically flat surfaces, and demonstrate that only constant-height STS is capable of mapping the intrinsic LDOS. In the constant-current STS, commonly used and easier-to-implement, the tip-sample distance variations imposed by the feedback loop result in set-point-dependent STS images and possibly mislead the identification of the CDW gap edges.

7 pages, 6 figures

References in corpus (7)

• Microscopic evidence for strong periodic lattice distortion in 2D charge-density wave systems
• Interplay of electron-electron and electron-phonon interactions in the low temperature phase of 1T-TaS2
• Insight into the charge density wave gap from contrast inversion in topographic STM images
• Quasiparticle Interference Studies of Quantum Materials
• Real-space Observation of Incommensurate Spin Density Wave and Coexisting Charge Density Wave on Cr(001) surface
• Nanoscale visualization and spectral fingerprints of the charge order in ScV6Sn6 distinct from other kagome metals
• Dispersing artifacts in FT-STS: a comparison of set point effects across acquisition modes