Dispersing artifacts in FT-STS: a comparison of set point effects across acquisition modes

TL;DR

This paper compares different FT-STS acquisition modes and reveals how certain artifacts, dependent on tip stabilization methods, can mimic real physical features, potentially leading to misinterpretation.

Contribution

It systematically analyzes how measurement artifacts depend on acquisition modes in FT-STS, highlighting the impact of tip stabilization on data interpretation.

Findings

Artifacts vary with acquisition mode and tip stabilization method.

Simultaneous constant current feedback can produce dispersing features.

Artifacts can be mistaken for genuine physical phenomena.

Abstract

Fourier transform scanning tunneling spectroscopy (FT-STS), or quasiparticle interference (QPI), has become an influential tool for the study of a wide range of important materials in condensed matter physics. However, FT-STS in complex materials is often challenging to interpret, requiring significant theoretical input in many cases, making it crucial to understand potential artifacts of the measurement. Here, we compare the most common modes of acquiring FT-STS data and show through both experiment and simulations that artifact features can arise that depend on how the tip height is stabilized throughout the course of the measurement. The most dramatic effect occurs when a series of dI/dV maps at different energies are acquired with simultaneous constant current feedback; here a feature that disperses in energy appears that is not observed in other measurement modes. Such artifact features are similar to those arising from real physical processes in the sample and are susceptible to misinterpretation.