Topic
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: First-principles calculations predict ferromagnetic and antiferromagnetic alignment of the spin moment for individual Fe and Cr adatoms on a Co film, respectively, implying negative spin polarization over the energy range of the Co surface state.
Abstract: We have used spin-polarized scanning tunneling spectroscopy to observe the spin polarization state of individual Fe and Cr atoms adsorbed onto Co nanoislands. These magnetic adatoms exhibit stationary out-of-plane spin polarization, but have opposite sign of the exchange coupling between electron states of the adatom and the Co island surface state: Fe adatoms exhibit parallel spin polarization to the Co surface state while Cr adatoms exhibit antiparallel spin polarization. First-principles calculations predict ferromagnetic and antiferromagnetic alignment of the spin moment for individual Fe and Cr adatoms on a Co film, respectively, implying negative spin polarization for Fe and Cr adatoms over the energy range of the Co surface state.
67 citations
IBM1
TL;DR: In this article, the authors investigated the influence of Chemical Bonding on spin-polarized tunneling and the relationship of tunneling magnetoresistance to tunneling spin polarization.
Abstract: The sections in this article are
Introduction
Fundamentals of Magnetic Tunnel Junctions (MTJs)
Influence of Chemical Bonding on Spin-Polarized Tunneling
Influence of Wave-Function Symmetry on Spin-Polarized Tunneling
Relationship of Tunneling Magnetoresistance to Tunneling Spin Polarization
Temperature and Bias Voltage Dependence of TMR
Spin-Dependent Tunneling in Other Systems
Conclusion
67 citations
TL;DR: In this article, a scanning tunneling microscope was designed to operate in ultra-high vacuum together with sample cleaning and characterization, and the major component for vibration damping is an external isolation table.
67 citations
TL;DR: A self-consistent model of tunneling current in a nano- and subnano-meter metal-insulator-metal plasmonic junction is presented, by including the effects of space charge and exchange correlation potential.
Abstract: When two conductors are separated by a sufficiently thin insulator, electrical current can flow between them by quantum tunneling. This paper presents a self-consistent model of tunneling current in a nano- and subnano-meter metal-insulator-metal plasmonic junction, by including the effects of space charge and exchange correlation potential. It is found that the J-V curve of the junction may be divided into three regimes: direct tunneling, field emission and space-charge-limited regime. In general, the space charge inside the insulator reduces current transfer across the junction, whereas the exchange-correlation potential promotes current transfer. It is shown that these effects may modify the current density by orders of magnitude from the widely used Simmons’ formula, which is only accurate for a limited parameter space (insulator thickness > 1 nm and barrier height > 3 eV) in the direct tunneling regime. The proposed self-consistent model may provide a more accurate evaluation of the tunneling current in the other regimes. The effects of anode emission and material properties (i.e. work function of the electrodes, electron affinity and permittivity of the insulator) are examined in detail in various regimes. Our simple model and the general scaling for tunneling current may provide insights to new regimes of quantum plasmonics.
67 citations
TL;DR: In this paper, the photothermal effect was employed to modulate the gap distance in a tunneling microscope, where optical heating induces the expansion and buckling of laser-illuminated sample surface.
Abstract: We have employed the photothermal effect to modulate the gap distance in a tunneling microscope In this approach, optical heating induces the expansion and buckling of laser‐illuminated sample surface The surface displacement can be modulated over a wide frequency range, and its height (typically <1 A) can be varied by changing the illumination intensity and modulation frequency This novel method provides an alternative means for performing tunneling spectroscopy and microscopy, and for determining work functions of materials
66 citations