Showing papers on "Scanning tunneling spectroscopy published in 1977"
TL;DR: This paper calculates the properties of a weak charge-transfer optical absorption band, whose predicted characteristics are a direct and simple consequence of the model that describes vibronically coupled tunneling.
77 citations
TL;DR: In this article, a correlation between tunneling mode intensity and orientation of the ring relative to the tunnel junction interface has been found for a series of halogen-substituted benzoic acids.
Abstract: Studies of inelastic tunneling spectra of nitro-substituted single aromatic ring compounds have shown a correlation between tunneling mode intensity and orientation of the ring relative to the tunnel junction interface. Details of the adsorption of substituent groups on the alumina barrier can also be deduced from the tunneling spectra. In a series of halogen-substituted benzoic acids where the ring orientation is relatively constant intensity changes for specific modes can be interpreted in terms of changes in the bond character with substitution. Tunneling spectra of tetracyanoquinodimethane (TCNQ), tetrathiafulvalene-tetracyanoquinodimethane, Li/sup +/(TCNQ)/sup -/, and TCNQ-d/sub 4/ have shown that for all derivatives the ionized form of the molecule is the species adsorbed on the alumina barrier. Analysis of the mode frequencies and intensities suggests that the Raman type of interaction makes dominant contributions to the tunneling intensity in TCNQ derivatives. Comparison of the tunneling intensities to calculated linear electron--phonon coupling constants for the TCNQ molecule shows that the magnitudes of tunneling intensity and coupling constant are correlated and can be identified with modes of the same symmetry.
57 citations
TL;DR: In this paper, a bridge that measures the difference between the tunneling spectra of doped and undoped junctions is proposed to minimize the background structure due to the metal electrodes and the oxide layer.
Abstract: Conventional, single junction inelastic electron tunneling spectra contain undesirable background structure due to the metal electrodes and the oxide layer. This structure can be minimized with a bridge that measures the difference between the tunneling spectra of doped and undoped junctions.
30 citations
26 citations
TL;DR: In this paper, it has been shown that resonant tunneling of electrons at room temperature has been found in nSi/SiO2/poly Si/Si O2/metal double-barriers.
Abstract: Evidence of resonant tunneling of electrons at room temperature has been found in nSi/SiO2/poly Si/SiO2/metal double-barriers. The observed singularities in the dc conductance curves have been explained as the tunneling through the quasistationary states of the potential well. The effective mass of tunneling electron and the Fermi level of polycrystalline Si have been determined from the measured resonant energies.
22 citations
TL;DR: In this article, the inelastic electron tunneling spectrum of a highly symmetric molecule, anthracene, was analyzed and it was shown that the vibrational frequencies as measured by tunneling agree well with optical measurements.
19 citations
TL;DR: In this paper, a trapezoidal barrier model of an insulating barrier between two free-electron model metals is used to investigate resonant tunneling across the insulator in the presence of a medium to large, externally applied electric field (bias).
5 citations
TL;DR: In this article, the PbHPO4 family is shown as a crystal where the tunneling mode is non-polar and, consequently, no frequency shift for the tunable mode in the polariton region can be caused besides the one produced by coupling with a polar optical phonon.
Abstract: For those tunneling systems (hydrogen bonded crystals) where the spontaneous polarization is directly due to the protonic array, the tunneling mode is polar and consequently it can couple with the internal macroscopic electric field. Our calculation shows that this coupling results in a mode with a strong wavevector and temperature dependence. The PbHPO4 family is indicated as a characteristic one to show modes with those properties.The classical KH2PO4 is shown as a crystal where the tunneling mode is non-polar and, consequently, no frequency shift for the tunneling mode in the polariton region can be caused besides the one produced by coupling with a polar optical phonon.