Abstract
One-dimensional (1D) stripe structures with a periodicity of 1.3 nm are formed by the 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 along the stripes and characteristic spectral peaks are observed by differential conductance () measurements, revealing the presence of 1D states on the surface. 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 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. The result is discussed in terms of electron localization into stripes due to strain-induced inhomogeneities and absorption from surface to bulk states.
- Received 20 July 2011
DOI:https://doi.org/10.1103/PhysRevB.84.195466
©2011 American Physical Society