Direct Momentum-Resolved Observation of One-Dimensional Confinement of Externally Doped Electrons within a Single Subnanometer-Scale Wire

Abstract

Cutting-edge research in the band engineering of nanowires at the ultimate fine scale is related to the minimum scale of nanowire-based devices. The fundamental issue at the subnanometer scale is whether angle-resolved photoemission spectroscopy (ARPES) can be used to directly measure the momentum-resolved electronic structure of a single wire because of the difficulty associated with assembling single wire into an ordered array for such measurements. Here, we demonstrated that the one-dimensional (1D) confinement of electrons, which are transferred from external dopants, within a single subnanometer-scale wire (subnanowire) could be directly measured using ARPES. Convincing evidence of 1D electron confinement was obtained using two different gold subnanowires with characteristic single metallic bands that were alternately and spontaneously ordered on a stepped silicon template, Si(553). Noble metal atoms were adsorbed at room temperature onto the gold subnanowires while the overall structure of the wires was maintained. Only one type of gold subnanowire could be controlled using external noble metal dopants without transforming the metallic band of the other type of gold subnanowires. This result was confirmed by scanning tunnelling microscopy experiments and first-principles calculations. The selective control clearly showed that externally doped electrons could be confined within a single gold subnanowire. This experimental evidence was used to further investigate the effects of the disorder induced by external dopants on a single subnanowire using ARPES.

Two-dimensional interaction of spin chains in the Si(553)-Au nanowire system

“…The former is assigned to the dimerization of the Au double row along the steps 22 . An ab-initio calculation confirmed that the dimerized double row Au chain in the middle of the terrace and a single honeycomb-like graphitic strip of Si atoms at the step edge is energetically most favorable 22 , which is consistent with STM 9,12,13,15,23,24 and XRD 20 studies. DFT calculations taking into account spin polarization led to the most recent structure model 6 referred to as original in the following.…”

Plasmon Standing Waves by Oxidation of Si(553)–Au

“…Recent studies on Si(hhk)-Au surfaces show that the gold-related bands are no longer free-electron-like, since they are strongly hybridized with the Si surface electronic states, particularly close to E F . [8][9][10][11] Hence, the nature of coupling between the wires and substrate defines the electronic properties of metallic chains.…”

Probing quasi-one-dimensional band structures by plasmon spectroscopy

“…According to angular resolved photoemission (ARPES) measurements [25,28,35], the Si(hhk)-Au systems are characterized by one or two-the number depends on the number of gold chains per terrace-parabolic electronic bands that cross the Fermi level. These bands are mostly located in the band gap of Si and make the systems metallic.…”