Scanning Tunneling Spectroscopy of Ag Films: The Effect of Periodic versus Quasiperiodic Modulation

Abstract

By using scanning tunneling spectroscopy to probe a silver thin film that contains both periodic and quasiperiodic modulation, and by using Fourier analysis, we unravel the influences of individual Fourier components of the scattering potential (periodic versus quasiperiodic) on the electronic structure of a onedimensional quasiperiodically modulated thin Ag film. Along the periodically modulated direction, a Bragg reflection-induced energy gap is observed in k space. On the other hand, the exotic E vs k spectrum with many minigaps was observed along the quasiperiodic direction.

Fourier analyses of commensurability oscillations in Fibonacci lateral superlattices

“…21 A wealth of exotic properties, such as localized or critical wave functions and a Cantor-set spectrum, are theoretically predicted, 22,23,24 with varieties of experimental systems devoted for their exploration. 25,26,27,28,29,30,31,32,33,34,35,36,37,38,39 It is therefore of great interest to perceive how the magnetotransport phenomena observed in a periodic 1D-LSL are altered (or remain unaltered) in a quasiperiodic 1D-LSL, as well as to search for phenomena peculiar to the quasiperiodic systems. The Fibonacci sequence typifies quasiperiodic systems in one-dimension.…”

A Single-Component Silicon Quasicrystal

“…In another publication by the same authors, that diffraction pattern was assigned, however, to tubule-like crystalline structures of silicon . A one-dimensional arrangement of crystalline stripes of silver about 1.5 nm high and of two widths (12.5 and 17.6 Å) deposited on cleaved GaAs(110) has been characterized through scanning tunneling spectroscopy and shown to follow the “silver mean” quasi-periodic distribution . To date, however, there has not been a conclusive report of a single-element quasicrystal that is itself not composed of crystalline particles.…”