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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 paper, the authors used scanning tunneling spectroscopy to investigate single InAs nanocrystals, 20char21{}70 \AA{} in diameter, in a highly asymmetric double barrier tunnel junction configuration.
Abstract: Scanning tunneling spectroscopy is used to investigate single InAs nanocrystals, 20\char21{}70 \AA{} in diameter, in a highly asymmetric double barrier tunnel junction configuration. The $I\ensuremath{-}V$ characteristics reflect contributions of both single-electron charging and the atomiclike level structure of the quantum dots. The spectra are simulated and well described within the framework of the ``orthodox model'' for single-electron tunneling. The peaks in the tunneling spectra display a systematic broadening with the reduction of dot diameter, from 40 to 150 meV over the studied quantum dot size range. This is assigned to a decreased electron dwell time on the dot, due to reduction of the barrier height, induced by the blueshift of the quantum-confined levels. The distribution of peak spacings within charging multiplets in the tunneling spectra is found to be Gaussian, resembling observations on metallic quantum dots.
64 citations
TL;DR: In this article, the authors show that in oxides, the correlation energy is small and the hybridization is strong and thus resonant tunneling through localized states at the Fermi energy can account for various tunnel anomalies observed in the normal or superconducting state.
64 citations
TL;DR: It is demonstrated that spin states of Co-porphyrin on Au(111) can be reversibly switched over by binding and unbinding of the NO molecule and can be sensed using scanning tunneling microscopy and spectroscopy (STM and STS).
Abstract: Controlling and sensing spin states of magnetic molecules at the single-molecule level is essential for spintronic molecular device applications. Here, we demonstrate that spin states of Co–porphyrin on Au(111) can be reversibly switched over by binding and unbinding of the NO molecule and can be sensed using scanning tunneling microscopy and spectroscopy (STM and STS). Before NO exposure, Co–porphryin showed a clear zero-bias peak, a signature of Kondo effect in STS, whereas after NO exposures, it formed a molecular complex, NO–Co–porphyrin, that did not show any zero-bias feature, implying that the Kondo effect was switched off by binding of NO. The Kondo effect could be switched back on by unbinding of NO through single-molecule manipulation or thermal desorption. Our density functional theory calculation results explain the observations with pairing of unpaired spins in dz2 and ppπ* orbitals of Co–porphyrin and NO, respectively. Our study opens up ways to control molecular spin state and Kondo effect ...
64 citations
TL;DR: This work exposes the crystalline surfaces of InAs nanowires with regular InP segments in vacuum while retaining the wire morphology through direct atomic scale imaging of the exterior surfaces of III-V nanowire surfaces by scanning tunneling microscopy (STM).
Abstract: We have succeeded in direct atomic scale imaging of the exterior surfaces of III-V nanowires by scanning tunneling microscopy (STM). By using atomic hydrogen, we expose the crystalline surfaces of InAs nanowires with regular InP segments in vacuum while retaining the wire morphology. We show images with atomic resolution of the two major types of InAs wurtzite nanowire surface facets and scanning tunneling spectroscopy (STS) data. Ab initio calculations of the lowest energy surface structures and simulated STM images, agree very well with experiments.
64 citations
TL;DR: A significant reduction of the fermionic tunneling energy is observed in an attractive Bose-Fermi mixture, which is attributed to an interaction-induced increase of the lattice depth due to the self-trapping of the atoms.
Abstract: We perform a detailed experimental study of the band excitations and tunneling properties of ultracold fermions in optical lattices. Employing a novel multiband spectroscopy for fermionic atoms, we can measure the full band structure and tunneling energy with high accuracy. In an attractive Bose-Fermi mixture we observe a significant reduction of the fermionic tunneling energy, which depends on the relative atom numbers. We attribute this to an interaction-induced increase of the lattice depth due to the self-trapping of the atoms.
64 citations