scholarly journals Electronic Structure and Bistable Conformational Study of the Tetraphenylporphyrin Erbium(III) Acetylacetonate Complex on the CaF2/Si(100) Surface at Low Temperatures

2021 ◽  
Author(s):  
Yitao Wang ◽  
Anne-Gaëlle Boyer ◽  
Hélène Sauriat-Dorizon ◽  
Eric Duverger ◽  
Damien Riedel
Keyword(s):  
Electronic Structure ◽  
Low Temperatures ◽  
Conformational Study ◽  
Acetylacetonate Complex

Mössbauer-Effekt von 57Fe und 119Sn in Palladiumlegierungen verschiedenen Wasserstoff-Gehaltes

1969 ◽  
Vol 24 (8) ◽  
pp. 1258-1265 ◽  
Author(s):  
M Mahnig ◽  
E Wicke
Keyword(s):  
Electronic Structure ◽  
Electron Concentration ◽  
Low Temperatures ◽  
Bound States ◽  
Experimental Methods ◽  
Magnetic Behaviour ◽  
Band Model ◽  
Direct Relation ◽  
Lattice Constants ◽  
Specific Heats

AbstractThe isomer shifts of 57Fe and 119Sn in Pd/Fe and Pd/Sn alloys of different compositions have been studied as functions of hydrogen content. In both systems the isomer shifts start to increase steeply at hydrogen contents which bring up the electron concentration in the alloy to 0.55 additional electrons per metal atom (compared to pure Pd). In accordance with results from other experimental methods each Fe atom has been found to donate 3 and each Sn atom 3.5 electrons to the bands of the alloy. The increase of the isomer shift is shown to follow the rise of the Fermi level when the bands are filled up gradually. It can be correlated to Friedel's model of virtual bound states. The results obtained confirm the connections developed earlier between the absorption of hydro-gen and the electronic structure of Pd and its alloys. They agree with conclusions drawn from magnetic behaviour and from electronic specific heats at low temperatures. They do not verify, how-ever, a direct relation to the lattice constants in these systems. It is not yet obvious how to correlate our results with the value of 0.36 d-holes in pure Pd obtained recently from measurements of the de Haas-van Alphen effect; possible deviations from the rigid-band model are discussed.

scholarly journals Minibands in twisted bilayer graphene probed by magnetic focusing

2020 ◽  
Vol 6 (16) ◽  
pp. eaay7838 ◽  
Author(s):  
A. I. Berdyugin ◽  
B. Tsim ◽  
P. Kumaravadivel ◽  
S. G. Xu ◽  
A. Ceferino ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Magnetic Fields ◽  
Long Range ◽  
Electron Scattering ◽  
Low Temperatures ◽  
Ballistic Transport ◽  
Bilayer Graphene ◽  
Degree Of Freedom ◽  
Magnetic Focusing ◽  
Twisted Bilayer Graphene

Magnetic fields force ballistic electrons injected from a narrow contact to move along skipping orbits and form caustics. This leads to pronounced resistance peaks at nearby voltage probes as electrons are effectively focused inside them, a phenomenon known as magnetic focusing. This can be used not only for the demonstration of ballistic transport but also to study the electronic structure of metals. Here, we use magnetic focusing to probe narrowbands in graphene bilayers twisted at ~2°. Their minibands are found to support long-range ballistic transport limited at low temperatures by intrinsic electron-electron scattering. A voltage bias between the layers causes strong minivalley splitting and allows selective focusing for different minivalleys, which is of interest for using this degree of freedom in frequently discussed valleytronics.

Electronic structure ofCsBi4Te6: A high-performance thermoelectric at low temperatures

2002 ◽  
Vol 65 (4) ◽  
Author(s):  
P. Larson ◽  
S. D. Mahanti ◽  
D.-Y. Chung ◽  
M. G. Kanatzidis
Keyword(s):  
Electronic Structure ◽  
Low Temperatures ◽  
High Performance

Geometric and Electronic Structure of Fullerene Film Growth as a Function of Coverage

1994 ◽  
Vol 359 ◽  
Author(s):  
B. Reihl
Keyword(s):  
Electronic Structure ◽  
Low Temperatures ◽  
Film Growth ◽  
Theoretical Calculations ◽  
Scanning Tunneling ◽  
Island Growth ◽  
Tunneling Microscopy ◽  
Adsorption Sites ◽  
Adsorbed Monolayer ◽  
Inverse Photoemission

ABSTRACTWe have employed scanning tunneling microscopy at room and low temperature, i.e. 300, 50, and 5 K, to study the epitaxy and growth of fullerene films on the noble-metal surfaces Ag(110) and Au(110). Initial island growth occurs on terrace sites away from substrate step edges. Particularly at low temperatures where the rotational and vibrational movements of the fullerene molecules are frozen in, different intra-molecular topographic patterns become visible in ordered films, which are characteristic of particular adsorption sites. Complementary tunneling spectroscopy and direct and inverse photoemission measurements reveal distinct differences between the first adsorbed monolayer and additional fullerene layers indicating differences in bonding and charge transfer. Our results are compared to theoretical calculations.

scholarly journals Electronic structure and conformational study of thiobiurets

1979 ◽  
Vol 88 (2) ◽  
pp. 91-100
Author(s):  
V. C. Jyothi Bhasu ◽  
D. N. Sathyanarayana ◽  
C. C. Patel
Keyword(s):  
Electronic Structure ◽  
Conformational Study

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

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