scholarly journals Transition of a two-dimensional spin mode to a helical state by lateral confinement

2015 ◽  
Vol 92 (23) ◽  
Author(s):  
P. Altmann ◽  
M. Kohda ◽  
C. Reichl ◽  
W. Wegscheider ◽  
G. Salis
Keyword(s):  
Two Dimensional ◽  
Spin Mode ◽  
Lateral Confinement ◽  
Helical State

scholarly journals 3/2 fractional quantum Hall plateau in confined two-dimensional electron gas

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Hailong Fu ◽  
Yijia Wu ◽  
Ruoxi Zhang ◽  
Jian Sun ◽  
Pujia Shan ◽  
...  
Keyword(s):  
Electron Gas ◽  
Quantum Hall ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Fractional Quantum ◽  
Edge Structure ◽  
Fractional Quantum Hall ◽  
Lateral Confinement ◽  
Dimensional Electron Gas

Abstract Even-denominator fractional quantum Hall (FQH) states, such as 5/2 and 7/2, have been well known in a two-dimensional electron gas (2DEG) for decades and are still investigated as candidates of non-Abelian statistics. In this paper, we present the observation of a 3/2 FQH plateau in a single-layer 2DEG with lateral confinement at a bulk filling factor of 5/3. The 3/2 FQH plateau is quantized at $$\left( {\frac{h}{{e^2}}} \right)/\left( {\frac{3}{2}} \right)$$ h e 2 ∕ 3 2 within 0.02%, and can survive up to 300 mK. This even-denominator FQH plateau may imply intriguing edge structure and excitation in FQH system with lateral confinement. The observations in this work demonstrate that understanding the effect of the lateral confinement on the many-body system is critical in the pursuit of important theoretical proposals involving edge physics, such as the demonstration of non-Abelian statistics and the realization of braiding for fault-tolerant quantum computation.

Epitaxial Growth of NiSi2 and CoSi2 on Laterally Confined Silicon by Rapid Thermal Annealing

1989 ◽  
Vol 146 ◽  
Author(s):  
H.F. Hsu ◽  
J.J. Chu ◽  
L.J. Chen
Keyword(s):  
Electron Beam ◽  
Epitaxial Growth ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Metal Films ◽  
Electron Beam Evaporation ◽  
Two Dimensional ◽  
Geometrical Configuration ◽  
Lateral Confinement ◽  
Stress Levels

ABSTRACTEpitaxial growth of NiSi2 and CoSi2 on silicon inside miniature oxide openings by rapid thermal annealing has been studied. Effects of lateral confinement, including two-dimensional and linear oxide openings, as well as deposition methods on the growth of NiSi2 and CoSi2 on silicon were investigated. Vast difference found in the behaviors of the growth of epitaxy inside oxide openings between samples with the metal films deposited by electron beam evaporation and sputtering are attributed to the differences in the geometrical configuration of the films and stress levels as well as surface cleanliness.

Dissipative Quantum Dynamics: The Role of the Lateral Confinement

1997 ◽  
Vol 11 (29) ◽  
pp. 3409-3418
Author(s):  
C. C. Wan ◽  
Ying Huang ◽  
Hong Guo
Keyword(s):  
Electron Transport ◽  
Quantum Wire ◽  
Quantum Dynamics ◽  
Type Model ◽  
Electron Drift ◽  
Two Dimensional ◽  
Quantum Dissipation ◽  
Lateral Confinement ◽  
Confining Potential

The dissipative quantum dynamics of electron transport in a two dimensional quantum wire is studied. The wire is modeled by a parabolic confining potential in one of the spatial directions. Quantum dissipation is provided by the electron coupling to a phonon bath using a simplified Fröhlich type model, and the problem is solved in closed form. We find that the lateral electron sub-bands give rise to a quasi-periodic behavior of a quantity which is essentially the transport impedance, and this leads to very different behavior of the electron drift velocity as compared to the case without lateral confinement.

scholarly journals The structure and origin of confined Holmboe waves

2018 ◽  
Vol 848 ◽  
pp. 508-544 ◽  
Author(s):  
Adrien Lefauve ◽  
J. L. Partridge ◽  
Qi Zhou ◽  
S. B. Dalziel ◽  
C. P. Caulfield ◽  
...  
Keyword(s):  
Shear Flow ◽  
Coherent Structure ◽  
Shear Flows ◽  
Three Dimensional ◽  
Finite Amplitude ◽  
Geophysical Flows ◽  
Two Dimensional ◽  
Lateral Confinement ◽  
Stratified Shear Flow ◽  
Spatio Temporal

Finite-amplitude manifestations of stratified shear flow instabilities and their spatio-temporal coherent structures are believed to play an important role in turbulent geophysical flows. Such shear flows commonly have layers separated by sharp density interfaces, and are therefore susceptible to the so-called Holmboe instability, and its finite-amplitude manifestation, the Holmboe wave. In this paper, we describe and elucidate the origin of an apparently previously unreported long-lived coherent structure in a sustained stratified shear flow generated in the laboratory by exchange flow through an inclined square duct connecting two reservoirs filled with fluids of different densities. Using a novel measurement technique allowing for time-resolved, near-instantaneous measurements of the three-component velocity and density fields simultaneously over a three-dimensional volume, we describe the three-dimensional geometry and spatio-temporal dynamics of this structure. We identify it as a finite-amplitude, nonlinear, asymmetric confined Holmboe wave (CHW), and highlight the importance of its spanwise (lateral) confinement by the duct boundaries. We pay particular attention to the spanwise vorticity, which exhibits a travelling, near-periodic structure of sheared, distorted, prolate spheroids with a wide ‘body’ and a narrower ‘head’. Using temporal linear stability analysis on the two-dimensional streamwise-averaged experimental flow, we solve for three-dimensional perturbations having two-dimensional, cross-sectionally confined eigenfunctions and a streamwise normal mode. We show that the dispersion relation and the three-dimensional spatial structure of the fastest-growing confined Holmboe instability are in good agreement with those of the observed confined Holmboe wave. We also compare those results with a classical linear analysis of two-dimensional perturbations (i.e. with no spanwise dependence) on a one-dimensional base flow. We conclude that the lateral confinement is an important ingredient of the confined Holmboe instability, which gives rise to the CHW, with implications for many inherently confined geophysical flows such as in valleys, estuaries, straits or deep ocean trenches. Our results suggest that the CHW is an example of an experimentally observed, inherently nonlinear, robust, long-lived coherent structure which has developed from a linear instability. We conjecture that the CHW is a promising candidate for a class of exact coherent states underpinning the dynamics of more disordered, yet continually forced stratified shear flows.

Spectrophotometric measurements of objective-prism spectra

1966 ◽  
Vol 24 ◽  
pp. 118-119
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
Progress Report ◽  
Two Dimensional ◽  
Objective Prism ◽  
Made In

I should like to give you a very condensed progress report on some spectrophotometric measurements of objective-prism spectra made in collaboration with H. Leicher at Bonn. The procedure used is almost completely automatic. The measurements are made with the help of a semi-automatic fully digitized registering microphotometer constructed by Hög-Hamburg. The reductions are carried out with the aid of a number of interconnected programmes written for the computer IBM 7090, beginning with the output of the photometer in the form of punched cards and ending with the printing-out of the final two-dimensional classifications.

Introductory paper

1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan
Keyword(s):  
Line Intensity ◽  
Classification Scheme ◽  
Two Dimensional ◽  
Spectral Classification ◽  
Dimensional Array ◽  
Rr Lyrae ◽  
Metallic Line ◽  
Introductory Paper ◽  
Parameter Varying ◽  
Definition Of

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

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