Search results for "TUNNEL"
showing 10 items of 576 documents
Analysis of image formation with a photon scanning tunneling microscope
1996
International audience; The photon scanning tunneling microscope (PSTM) is based on the frustration of a total internal reflected beam by the end of an optical fiber. Until now it has been used to obtain topographic information, generally for smooth samples. We report theoretical as well as experimental results on the observation of a step on a quartz substrate with the PSTM. These results demonstrate the effects on image formation of the distance between the fiber tip and the sample surface, the orientation of the incident beam with respect to the step, the polarization, and the coherence of the light. Good agreement exists between numerical simulations and experiments. We show that a pert…
L-Tryptophan on Cu(111): engineering a molecular labyrinth driven by indole groups
2015
The present article investigates the adsorption and molecular orientation of L-Tryptophan, which is both an essential amino acid important for protein synthesis and of particular interest for the development of chiral molecular electronics and biocompatible processes and devices, on Cu(111) using scanning tunneling microscopy and spectroscopy at 55 K and at room temperature. The arrangement of chemisorbed L-Tryptophan on the copper surface varies with both temperature and surface coverage. At low coverage, small clusters form on the surface irrespective of temperature, while at high coverage an ordered chain structure emerges at room temperature, and a tightly packed structure forms a molec…
Exploring the Role of Intramolecular Interactions in the Suppression of Quantum Tunneling of the Magnetization in a 3d-4f Single-Molecule Magnet.
2021
Hydroxide-bridged FeIII4LnIII2 clusters having the general formula [Fe4Ln2(μ3-OH)2(mdea)6(SCN)2(NO3)2(H2O)2]·4H2O·2MeCN {Ln = Y (1), Dy (2), mdea = N-methyldiethanolamine} were synthesized and magnetically characterized. The thermal relaxation of the magnetization for 2 and the diluted FeIII4DyIIIYIII complex 3 (with and without applied field) has been analyzed. The diluted sample shows a dominant QTM at low temperatures that can be removed with a 0.15 T dc field. Both 2 and 3 show moderately high Ueff barriers and exhibit hysteresis loops until 5 K.
Role of Deprotonation and Cu Adatom Migration in Determining the Reaction Pathways of Oxalic Acid Adsorption on Cu(111)
2011
Scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and first principles theoretical calculations have been used to gain insight into the fundamental processes involved in the adsorption and self-assembly of oxalic acid on Cu(111). The experimental data demonstrate that several reaction pathways are involved in the chemisorption of oxalic acid on Cu(111), one of which leads to deprotonation of the acid into oxalate molecules that form ordered structures on the surface. Theoretical calculations indicate that the adsorption of oxalate molecules is not stable on the surface unless copper adatoms are taken into consideration. Coordination with copper adatoms prevents ox…
Network Virtualization Based on Effective Packet Transformations
2015
Promocijas darbā ir piedāvātas divas oriģinālas tehnoloģijas, kas paaugstina datortīklu virtualizēšanas efektivitāti: ZERO tunelēšanas protokols, un Pakešu Transformāciju Valoda (Packet Transformation Language, PTL), kas ļauj kompaktā pierakstā formāli aprakstīt ZERO un citus tunelēšanas protokolus. Darbā ir piedāvāts Ethernet-pāri-IP tunelēšanas protokols, kas nodala visus Ethernet kadrus tunelēšanai NICE un UGLY kadros. UGLY kadri tiek tunelēti ar tradicionālām metodēm, kā UDP vai GRE enkapsulācija, kas būtiski palielina kopējo paketes garumu dēļ papildus galvenēm un fragmentēšanas, kas parasti nepieciešama, lai transportētu garus Ethernet kadrus pāri IP datortīklam, kam parasti maksimāla…
Anatomic Posterolateral Knee Reconstructions Require a Popliteofibular Ligament Reconstruction Through a Tibial Tunnel
2010
Background: No biomechanical study has been performed analyzing the merits of reconstructing the popliteofibular ligament (PFL) through a tibial tunnel with an anatomic reconstruction of the posterolateral knee. Hypothesis: There is no difference in an anatomic posterolateral knee reconstruction with or without a PFL reconstruction placed through a tibial tunnel in restoring knee motion to the intact, uninjured state, and the knee is not overconstrained with this reconstruction. Study Design: Controlled laboratory study. Methods: Eight paired knees were tested in the intact state and then sectioned to simulate a grade III posterolateral knee injury. The reconstruction for the first paired …
Charge transport through spin-polarized tunnel junction between two spin-split superconductors
2019
We investigate transport properties of junctions between two spin-split superconductors linked by a spin-polarized tunneling barrier. The spin-splitting fields in the superconductors (S) are induced by adjacent ferromagnetic insulating (FI) layers with arbitrary magnetization. The aim of this study is twofold: On the one hand, we present a theoretical framework based on the quasiclassical Green's functions to calculate the Josephson and quasiparticle current through the junctions in terms of the different parameters characterizing it. Our theory predicts qualitative new results for the tunneling differential conductance, $dI/dV$, when the spin-splitting fields of the two superconductors are…
Tunneling junctions of the heavy-fermion superconductor UPd2Al3
1998
Abstract Tunneling spectroscopy on planar Giaever-type junctions is a powerful tool for the investigation of the superconducting state of metals. Since it is possible to prepare high-quality epitaxial thin films of the heavy-fermion compound UPd 2 Al 3 , this method can be used to examine the energy gap of this presumably unconventional superconductor. We prepared cross-junctions consisting of a UPd 2 Al 3 base electrode and a metal counter electrode (Au, Al or Ag). These small area contacts without artificial barriers have only low junction resistances and suffer from irreproducibility. On the other hand, on some of those junctions we observed BCS-like tunneling conductivity. In order to i…
Time Evolution of two distant SQUID rings irradiated with entangled electromagnetic field
2006
Two distant mesoscopic SQUID rings are irradiated with two mode microwaves produced by the same source. The time evolution of the system is studied. The two microwave modes are correlated. It is shown that the currents tunnelling through the Josephson junctions in the distant rings, are also correlated.
Very large thermophase in ferromagnetic josephson junctions
2014
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