Observation of surface morphology by reflection electron holography

1989 ◽  
Vol 47 ◽  
pp. 536-537
Author(s):  
N. Osakabe ◽  
J. Endo ◽  
T. Matsuda ◽  
A. Tonomura
Keyword(s):  
Phase Shift ◽  
Surface Morphology ◽  
High Sensitivity ◽  
High Energy ◽  
Path Difference ◽  
Transmission Mode ◽  
Electron Holography ◽  
Dynamical Process ◽  
High Vertical Resolution ◽  
Amplification Technique

Progress in microscopy such as STM and TEM-TED has revealed surface structures in atomic dimension. REM has been used for the observation of surface dynamical process and surface morphology. Recently developed reflection electron holography, which employes REM optics to measure the phase shift of reflected electron, has been proved to be effective for the observation of surface morphology in high vertical resolution ≃ 0.01 Å.The key to the high sensitivity of the method is best shown by comparing the phase shift generation by surface topography with that in transmission mode. Difference in refractive index between vacuum and material Vo/2E≃10-4 owes the phase shift in transmission mode as shownn Fig. 1( a). While geometrical path difference is created in reflection mode( Fig. 1(b) ), which is measured interferometrically using high energy electron beam of wavelength ≃0.01 Å. Together with the phase amplification technique , the vertivcal resolution is expected to be ≤0.01 Å in an ideal case.

High-sensitivity external modulator data link for high-energy particle detector diagnostics

1993 ◽  
Author(s):  
Kent G. McCammon ◽  
Mark E. Lowry ◽  
Yuan-Hann Chang ◽  
Paul J. Parker ◽  
Bolek Wyslouch ◽  
...  
Keyword(s):  
High Sensitivity ◽  
High Energy ◽  
High Energy Particle ◽  
Particle Detector ◽  
Energy Particle ◽  
Data Link

Electron Refraction of Amorphous Nanospheres

1997 ◽  
Vol 3 (S2) ◽  
pp. 1055-1056
Author(s):  
Y.C. Wang ◽  
T.M. Chou ◽  
M. Libera
Keyword(s):  
Refractive Index ◽  
Electron Scattering ◽  
Unit Volume ◽  
High Energy ◽  
Covalent Bonding ◽  
Electron Holography ◽  
High Energy Electron ◽  
Electron Wave ◽  
Transmission Electron ◽  
The Mean

The phase shift imparted to an incident high-energy electron wave in a TEM is related to the specimen’s electron-refractive properties. These, in turn, are related to the electrostatic potential and, by Fourier transform (1), to the electron scattering factors fei(s) for the various atom species i in the specimen and scattering vectors s. The average refractive index is determined by the mean electrostatic (inner) potential, Φo, and can be modelled as Φo = (C/Ω) Σfei(s0) [equation 1] where C = 47.878 (V-Å2) and the summation runs over all of the atoms in the unit volume Ω (2). Calculated fei(s) data are available from the literature (e.g. 3). These calculations have only been done for neutral atoms and some fully ionized cations and anions. They do not account for electron redistribution due to covalent bonding to which Φo is quite sensitive (4).This research is making Φo measurements using transmission electron holography. Holograms were collected using a 200keV Philips CM20 FEG TEM equipped with a non-rotatable biprism (5) and a Gatan 794 Multiscan camera.

scholarly journals CP VIOLATION AND BEAUTY DECAYS — A CASE STUDY OF HIGH IMPACT, HIGH SENSITIVITY AND EVEN HIGH PRECISION PHYSICS

2000 ◽  
Vol 15 (08) ◽  
pp. 1079-1156
Author(s):  
I. I. BIGI
Keyword(s):  
Cp Violation ◽  
Degrees Of Freedom ◽  
High Energy Physics ◽  
Dipole Moments ◽  
High Sensitivity ◽  
High Energy ◽  
New Physics ◽  
B Decays ◽  
New Paradigm ◽  
Parametric Reliability

The narrative of these lectures contains three main threads: (i) CP violation despite having so far been observed only in the decays of neutral kaons has been recognized as a phenomenon of truly fundamental importance. The KM ansatz constitutes the minimal implementation of CP violation: without requiring unknown degrees of freedom it can reproduce the known CP phenomenology in a nontrivial way. (ii) The physics of beauty hadrons — in particular their weak decays — opens a novel window onto fundamental dynamics: they usher in a new quark family (presumably the last one); they allow us to determine fundamental quantities of the Standard Model like the b quark mass and the CKM parameters V(cb), V(ub), V(ts) and V(td); they exhibit speedy or even rapid [Formula: see text] oscillations. (iii) Heavy Quark Expansions allow us to treat B decays with an accuracy that would not have been thought possible a mere decade ago. These three threads are joined together in the following manner: (a) Huge CP asymmetries are predicted in B decays, which represents a decisive test of the KM paradigm for CP violation. (b) Some of these predictions are made with high parametric reliability, which (c) can be translated into numerical precision through the judicious employment of novel theoretical technologies. (d) Beauty decays thus provide us with a rich and promising field to search for New Physics and even study some of its salient features. At the end of it there might quite possibly be a New Paradigm for High Energy Physics. There will be some other threads woven into this tapestry: electric dipole moments, and CP violation in other strange and in charm decays.

scholarly journals Suppressing Geometric Phase Shift Owing to Antiphase Boundaries in Dark-Field Electron Holography

2019 ◽  
Vol 60 (5) ◽  
pp. 698-703
Author(s):  
Youngji Cho ◽  
Kodai Niitsu ◽  
Yoshihiro Midoh ◽  
Koji Nakamae ◽  
Daisuke Shindo ◽  
...  
Keyword(s):  
Phase Shift ◽  
Geometric Phase ◽  
Dark Field ◽  
Electron Holography ◽  
Antiphase Boundaries ◽  
Field Electron ◽  
Dark Field Electron

scholarly journals Transient energy growth of channel flow with cross-flow

2019 ◽  
Vol 286 ◽  
pp. 07008
Author(s):  
J. Benyza ◽  
M. Lamine ◽  
A. Hifdi
Keyword(s):  
Flow Rate ◽  
Initial Conditions ◽  
Cross Flow ◽  
High Sensitivity ◽  
Maximum Growth ◽  
Growth Function ◽  
High Energy ◽  
Optimal Perturbation ◽  
Energy Growth ◽  
Transient Energy

The effect of a uniform cross flow (injection/ suction) on the transient energy growth of a plane Poiseuille flow is investigated. Non-modal linear stability analysis is carried out to determine the two-dimensional optimal perturbations for maximum growth. The linearized Navier-Stockes equations are reduced to a modified Orr Sommerfeld equation that is solved numerically using a Chebychev collocation spectral method. Our study is focused on the response to external excitations and initial conditions by examining the energy growth function G(t) and the pseudo-spectrum. Results show that, the transient energy of the optimal perturbation grows rapidly at short times and decline slowly at long times when the cross-flow rate is low or strong. In addition, the maximum energy growth is very pronounced in low injection rate than that of the strong one. For the intermediate cross-flow rate, the transient energy growth of the perturbation, is only possible at the long times with a very high-energy gain. Analysis of the pseudo-spectrum show that the non-normal character of the modified Orr-Sommerfeld operator tends to a high sensitivity of pseudo-spectra structures.

The Surface Morphology and Characterisation of Electronic Properties of Boron Implanted Microwave Plasma CVD Diamond Films by Atomic Force and Scanning Tunneling Microscopies

1998 ◽  
Vol 4 (S2) ◽  
pp. 332-333
Author(s):  
A. G. Fitzgerald ◽  
Y. Fan ◽  
P. John ◽  
C. E. Troupe ◽  
J. I. B. Wilson
Keyword(s):  
Surface Morphology ◽  
Electronic Properties ◽  
Microwave Plasma ◽  
Diamond Films ◽  
High Energy ◽  
Scanning Tunneling Spectroscopy ◽  
Morphological Features ◽  
Scanning Tunneling ◽  
Crystal Surfaces ◽  
Atomic Force

The surface morphology and electronic properties of a low energy boron implanted diamond films with shallow doping, prepared by microwave plasma enhanced chemical vapour deposition (CVD), have been characterised by atomic force microscopy (AFM), scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) techniques.Both AFM and STM images taken at different locations on the films have exhibited similar morphological features on the (100) crystal surfaces. The crystal surfaces are not atomically flat but are composed of many hillocks as shown in Fig 1(a) to 1(c). The majority of values measured from the peaks of hillocks to the valleys are in the range of 2 to 5 nm, and the diameter of these hillocks is in the range of 50 to 250 nanometers. These crystal surface morphological features are believed to be caused in the high energy boron ion implantation process.

Combinatorial optimization of atomically controlled growth for oxide films by the carrousel type laser molecular beam epitaxy

2001 ◽  
Vol 700 ◽  
Author(s):  
R. Takahashi ◽  
Y. Matsumoto ◽  
H. Koinuma ◽  
M. Lippmaa ◽  
M. Kawasaki
Keyword(s):  
Molecular Beam ◽  
Ybco Film ◽  
High Sensitivity ◽  
High Energy ◽  
In Situ Monitoring ◽  
Laser Deposition ◽  
Crystal Habit ◽  
Laser Focusing ◽  
The One

AbstractA new combinatorial pulsed laser deposition system has been developed for rapid optimization of epitaxial growth process by using a carrousel type masking plate. Under in-situ monitoring of growing surface with reflection high energy electron diffraction, eight films with different compositions or preparation parameters can be fabricated on a single substrate. By using this system, we have succeeded in the one lot optimization of YBa2Cu3O7-d(YBCO), PrGaO3, SrO and BaO film growths on the B-site (TiO2) terminated SrTiO3(001) substrates. Key results from these experiments include the high sensitivity of YBCO film crystallinity to the laser focusing as well as of growth behavior of epitaxial SrO and BaO films to the crystal habit with the underlying atomic layers.

Determination of the Inelastic Mean-Free-Path and Mean Inner Potential for AlAs and GaAs Using Off-Axis Electron Holography and Convergent Beam Electron Diffraction

2007 ◽  
Vol 13 (5) ◽  
pp. 329-335 ◽  
Author(s):  
Suk Chung ◽  
David J. Smith ◽  
Martha R. McCartney
Keyword(s):  
Electron Diffraction ◽  
Theoretical Calculations ◽  
Mean Free Path ◽  
High Energy ◽  
Convergent Beam Electron Diffraction ◽  
Electron Holography ◽  
Beam Electron ◽  
The Mean ◽  
Convergent Beam ◽  
Inelastic Mean Free Path

The mean-free-paths for inelastic scattering of high-energy electrons (200 keV) for AlAs and GaAs have been determined based on a comparison of thicknesses as measured by electron holography and convergent-beam electron diffraction. The measured values are 77 ± 4 nm and 67 ± 4 nm for AlAs and GaAs, respectively. Using these values, the mean inner potentials of AlAs and GaAs were then determined, from a total of 15 separate experimental measurements, to be 12.1 ± 0.7 V and 14.0 ± 0.6 V, respectively. These latter measurements show good agreement with recent theoretical calculations within experimental error.

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