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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.
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TL;DR: In this article, a simple tight-binding model was proposed to explain the geometry of the defect states in the tunneling spectroscopy images of a single-input single-output (SISO) device.
Abstract: Scanning tunneling spectroscopy images of ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ doped with excess Bi reveal electronic defect states with a striking shape resembling clover leaves. With a simple tight-binding model, we show that the geometry of the defect states in ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ can be directly related to the position of the originating impurities. Only the Bi defects at the Se sites five atomic layers below the surface are experimentally observed. We show that this effect can be explained by the interplay of defect and surface electronic structure.
80 citations
TL;DR: In this paper, the authors measured the STM (scanning tunneling microscope) light emission spectra of Au atoms at 80 K with atomic spatial resolution, where the individual Au atoms along the rows could be resolved in the image.
Abstract: We have measured the STM (scanning tunneling microscope) light emission spectra of $\mathrm{Au}(110)\ensuremath{-}(2\ifmmode\times\else\texttimes\fi{}1)$ at 80 K with atomic spatial resolution. The individual Au atoms along the $(2\ifmmode\times\else\texttimes\fi{}1)$ rows could be resolved in the STM image. Distinctly different emission spectra are observed depending on whether the tip is located over the atomic row or over the valley between the rows. The spectrum obtained over the row atoms can be ascribed to the emission by localized surface plasmons. The spectrum found over the valley contains emission from excitations atomically localized in the valley.
80 citations
TL;DR: This work uses scanning tunneling spectroscopy (STS) to resolve two superconducting gaps with an energy difference of 150 μeV and shows that this is the result of a selective tunneling into the two bands at the energy of the two coherence peaks.
Abstract: The type I superconductor lead (Pb) has been theoretically predicted to be a two-band superconductor. We use scanning tunneling spectroscopy (STS) to resolve two superconducting gaps with an energy difference of $150\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$. Tunneling into Pb(111), Pb(110), and Pb(100) crystals reveals a strong dependence of the two coherence peak intensities on the crystal orientation. We show that this is the result of a selective tunneling into the two bands at the energy of the two coherence peaks. This is further sustained by the observation of signatures of the Fermi sheets in differential conductance maps around subsurface defects. A modification of the density of states of the two bands by adatoms on the surface confirms the different orbital character of each of the two subbands.
80 citations
Patent•
03 Jul 1997TL;DR: In this paper, a system for determining a non-contact, near-surface generation and recombination lifetimes and near surface doping of a semiconductor material is presented, which includes a radiation pulse source that biases a dielectric on top of the semiconductor, a voltage sensor to sense the surface voltage, and a photon source to create carriers.
Abstract: The present invention is directed to a system for, and method of, determining a non-contact, near-surface generation and recombination lifetimes and near surface doping of a semiconductor material. The system includes: (1) a radiation pulse source that biases a dielectric on top of the semiconductor material, (2) a voltage sensor to sense the surface voltage, and (3) a photon source to create carriers. For lifetime measurements both the excitation and measurement signals are time dependent and may be probed near the surface of the semiconductor to obtain various electrical properties. For high-field tunneling and leakage characteristics of a thin dielectric (<15 nm) on top of the semiconductor, a high bias charge density is used to induce tunneling, from which tunneling fields and charge-fluence to tunneling of the dielectric are determined.
80 citations
TL;DR: In this article, the confinement of the Ag(111) surface state by a porous organic network is studied with maps obtained under constant-current (CC) as well as open-feedback-loop (OFL) conditions.
Abstract: Scanning tunneling spectroscopy (STS) enables the local, energy-resolved investigation of a samples surface density of states (DOS) by measuring the differential conductance (dI/dV) being approximately proportional to the DOS. It is popular to examine the electronic structure of elementary samples by acquiring dI/dV maps under constant current conditions. Here we demonstrate the intricacy of STS mapping of samples exhibiting a strong corrugation originating from electronic density and local work function changes. The confinement of the Ag(111) surface state by a porous organic network is studied with maps obtained under constant-current (CC) as well as open-feedback-loop (OFL) conditions. We show how the CC maps deviate markedly from the physically more meaningful OFL maps. By applying a renormalization procedure to the OFL data we can mimic the spurious effects of the CC mode and thereby rationalize the physical effects evoking the artefacts in the CC maps.
80 citations