One-dimensional surface states on a striped Ag thin film with stacking fault arrays

TL;DR

This study investigates one-dimensional surface states on striped silver thin films with stacking faults, revealing quantum confinement effects and characterizing their electronic properties using scanning tunneling microscopy.

Contribution

It demonstrates that stacking faults induce 1D surface states in Ag thin films and models their confinement with a single quantum well, contrasting with previous 2D models.

Findings

Observation of 1D standing waves on surface stripes

Effective potential barrier estimated from measurements

Single quantum well model reproduces spectral features

Abstract

One-dimensional (1D) stripe structures with a periodicity of 1.3 nm are formed by introduction of stacking fault arrays into a Ag thin film. The surface states of such striped Ag thin films are studied using a low temperature scanning tunneling microscope. Standing waves running in the longitudinal direction and characteristic spectral peaks are observed by differential conductance (dI/dV) measurements, revealing the presence of 1D states on the surface stripes. Their formation can be attributed to quantum confinement of Ag(111) surface states into a stripe by stacking faults. To quantify the degree of confinement, the effective potential barrier at the stacking fault for Ag(111) surface states is estimated from independent measurements. A single quantum well model with the effective potential barrier can reproduce the main features of dI/dV spectra on stripes, while a Kronig-Penney model fails to do so. Thus the present system should be viewed as decoupled 1D states on individual stripes rather than as anisotropic 2D Bloch states extending over a stripe array.