Scanning tunneling spectroscopy

About: Scanning tunneling spectroscopy is a research topic. Over the lifetime, 7886 publications have been published within this topic receiving 213828 citations.

Determination of the local electronic structure of atomic‐sized defects on Si(001) by tunneling spectroscopy

Abstract: Tunneling spectroscopy and voltage‐dependent scanning tunneling microscopy have been used to study the geometry and electronic properties of atomic‐sized defects on the Si(001) surface. Individual dimer vacancies are shown to be semiconducting, consistent with the π‐bonded defect model of Pandey. Another type of characteristic defect is found which gives rise to strongly metallic tunneling I–V characteristics, demonstrating that it has a high density of states at the Fermi level and is likely active in Fermi level pinning on Si(001). Spatially dependent I–V measurements and tunneling barrier height measurements also directly reveal the spatial extent of this metallic character and provide direct measures of the ‘‘size’’ of the defects.

Two-dimensional oxide on Pd(111).

Abstract: The oxidation of Pd(111) leads to an incommensurate surface oxide, which was studied by the use of scanning tunneling microscopy, surface x-ray diffraction, high resolution core level spectroscopy, and density functional calculations. A combination of these methods reveals a two-dimensional structure having no resemblance to bulk oxides of Pd. Our study also demonstrates how the atomic arrangement of a nontrivial incommensurate surface can be solved by molecular dynamics in a case where experimental techniques alone give no solution.

Atomic-scale characterization of nitrogen-doped graphite: Effects of dopant nitrogen on the local electronic structure of the surrounding carbon atoms

Abstract: We report on the local atomic and electronic structures of a nitrogen-doped graphite surface by scanning tunneling microscopy, scanning tunneling spectroscopy, x-ray photoelectron spectroscopy, and first-principles calculations. The nitrogen-doped graphite was prepared by nitrogen ion bombardment followed by thermal annealing. Two types of nitrogen species were identified at the atomic level: pyridinic-N (N bonded to two C nearest neighbors) and graphitic-N (N bonded to three C nearest neighbors). Distinct electronic states of localized π states were found to appear in the occupied and unoccupied regions near the Fermi level at the carbon atoms around pyridinic-N and graphitic-N species, respectively. The origin of these states is discussed based on experimental results and theoretical simulations.

Voltage-controlled spin selection in a magnetic resonant tunneling diode.

Abstract: We have fabricated all II-VI semiconductor resonant tunneling diodes based on the (Zn,Mn,Be)Se material system, containing dilute magnetic material in the quantum well, and studied their current-voltage characteristics. When subjected to an external magnetic field the resulting spin splitting of the levels in the quantum well leads to a splitting of the transmission resonance into two separate peaks. This is interpreted as evidence of tunneling transport through spin polarized levels, and could be the first step towards a voltage controlled spin filter.