Visualizing Quantum Well State Perturbations of Metallic Thin Films near Stacking Fault Defects

TL;DR

This paper investigates how intrinsic defects in metallic thin films cause significant local perturbations in quantum well states, revealing strong energy and spatial variations within a few nanometers.

Contribution

It provides a detailed experimental analysis of quantum well state perturbations near defects and introduces a simple model to describe these energetic fluctuations.

Findings

Quantum well states are highly perturbed near defects within 4 nm.

Energetic fluctuations can reach up to 100 meV.

Perturbations show spatial asymmetries in LDOS around defects.

Abstract

We demonstrate that quantum well states (QWS) of thin Pb films are highly perturbed within the proximity of intrinsic film defects. Scanning Tunneling Spectroscopy (STM/STS) measurements indicate that the energy of these states have a strong distance dependence within 4 nm of the defect with the strongest energetic fluctuations equaling up to 100 meV. These localized perturbations show large spatially-dependent asymmetries in the LDOS around the defect site for each corresponding quantum well state. These energetic fluctuations can be described by a simple model which accounts for fluctuations in the confinement potential induced by topographic changes.