Local-Scale Spectroscopic Studies of Vortex Organization in Mesoscopic Superconductors

2017 ◽  
Author(s):  
D. Roditchev ◽  
T. Cren ◽  
C. Brun ◽  
M.V. Milošević
Keyword(s):  
Spectroscopic Studies ◽  
Local Scale ◽  
Scanning Tunneling ◽  
Vortex Matter ◽  
Tunneling Microscopy ◽  
Vortex States ◽  
Bulk Superconductors ◽  
Josephson Vortices ◽  
Mesoscopic Superconductors ◽  
Different Levels

This article examines the vortex matter of mesoscopic superconductors with numerous vortex states that do not exist in bulk superconductors. Using scanning tunneling microscopy/spectroscopy, it investigates the organization of vortex cores at different levels of confinement. The article begins with a discussion of the basic properties of quantum vortices in superconductors and experimental requirements for studying vortex confinement phenomena. It then considers the effect of sample size and shape on vortex distribution and pinning, along with the resulting ultra-dense configurations that cannot be achieved in bulk superconductors. It also describes the peculiar features of vortices in atomically thin superconductors having mixed Abrikosov–Josephson vortices.

COMBINED HRLEED AND STM INVESTIGATIONS ON THE INITIAL STAGES OF Cu HETEROEPITAXY Ru(0001)

1997 ◽  
Vol 04 (06) ◽  
pp. 1167-1171 ◽  
Author(s):  
CH. AMMER ◽  
K. MEINEL ◽  
H. WOLTER ◽  
A. BECKMANN ◽  
H. NEDDERMEYER
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Strain Relaxation ◽  
Local Scale ◽  
Low Energy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Layer Structures ◽  
Low Energy Electron

Recent scanning tunneling microscopy (STM) observations revealed different layer structures in the heteroepitaxial Cu/Ru(0001) system with increasing film thickness attributed to various stages of strain relaxation. High-resolution low-energy electron diffraction (HRLEED) analysis permits one to derive more exactly both lattice periodicities and lattice rotations. Furthermore, the representative character of local STM results can be proved. However, STM measurements are needed to identify and to assign the satellite spots to coexistent different superstructures which are superposed incoherently in the diffraction pattern. Generally, the integral LEED results confirm the crystallographic data obtained by STM in a local scale.

Scanning Tunneling Microscopy Studies of GaAs1-xPx Single Crystals

1995 ◽  
Vol 378 ◽  
Author(s):  
X. Liu ◽  
E. R. Weber ◽  
D. F. Ogletree ◽  
M. Salmeron ◽  
T. Slupinski
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Single Crystals ◽  
Spectroscopic Studies ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Cross Sectional ◽  
Group V ◽  
Imaging Results ◽  
The Difference

AbstractWe report cross-sectional scanning tunneling microscopy studies of GaAsP single crystals grown by the Liquid Encapsulated Czochralski technique. We show that the two group-V elements can be clearly distinguished, which is attributed to the difference in energies of surface dangling bond states of As and P. Our atomic scale imaging results show alloy composition in agreement with spectroscopic studies. They also provide valuable information about atomic scale alloy fluctuations and clustering effects.

Proximity Effect A New Insight from In Situ Fabricated Hybrid Nanostructures

2017 ◽  
Author(s):  
J.C. Cuevas ◽  
D. Roditchev ◽  
T. Cren ◽  
C. Brun
Keyword(s):  
Density Of States ◽  
Proximity Effect ◽  
Historical Review ◽  
Hybrid Nanostructures ◽  
Scanning Tunneling ◽  
Small Length ◽  
Tunneling Microscopy ◽  
Josephson Vortices ◽  
Low Dimensional

This article investigates the proximity effect on small length and energy scales in novel low-dimensional systems using in situ fabricated superconducting nanostructures (SNSs) and scanning tunneling microscopy/spectroscopy (STM/STS) techniques. After a brief historical review of research on superconductivity and the proximity effect, the article describes how to build a variety of in situ superconducting hybrid nanostructures and how to investigate the proximity density of states with the help of STM/STS. It then considers the proximity effect in a correlated 2D disordered metal and in diffusive SNS junctions before discussing proximity Josephson vortices. It also examines the proximity effect between two dissimilar superconductors and concludes by highlighting several fundamental problems related to proximity effect in the framework of quasiclassical microscopic Usadel theory.

Single electron charging effect in individual Si nanocrystals.

2000 ◽  
Vol 638 ◽  
Author(s):  
P. Gentile ◽  
T. Baron ◽  
N. Magnea ◽  
P. Mur ◽  
F. Martin ◽  
...  
Keyword(s):  
Coulomb Blockade ◽  
Chemical Vapor ◽  
Spectroscopic Studies ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Si Nanocrystals ◽  
Tunnel Resistance ◽  
Pressure Chemical ◽  
Charging Effect ◽  
Stm Images

AbstractWe present a detailed study of the electronics properties of individual silicon nano- crystals (nc-Si) elaborated by Low Pressure Chemical Vapor Deposition on 1.2 nm thick SiO2 grown on Si (100). The combination of ultra thin oxide layers and highly doped substrates allows imaging the hemispherical dots by Scanning Tunneling Microscopy. By analyzing the STM images, we deduce a size distribution, which ranges between 3 and 6 nm with a surface density around 1012 cm-2. Spectroscopic studies of single dots are made by recording the I(V) curves on the Si nanocrystal accurately selected with the metallic tip. These I(V) curves obtain on a single dot, exhibit Coulomb blockade and resonant tunneling effects. Coulomb pseudo gaps, Ec, between 0.15 and 0.2 V are measured for different dots. From the width and height of the staircases observed at bias greater than Ec, 60 meV and 40 pA respectively, capacitance of 0.5 to 1 aF and tunnel resistance of 3.5×108 and 5.7×109 Ohms are measured within the orthodox approximation for asymmetric junctions. We have determined, from experimental measurements, the energy of the first level confined in nc-Si.

STM studies of crystal growth

1991 ◽  
Vol 49 ◽  
pp. 374-375
Author(s):  
M. G. Lagally
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Sputter Deposition ◽  
Field Of View ◽  
Scanning Tunneling ◽  
Wide Field ◽  
Tunneling Microscopy ◽  
Wide Field Of View ◽  
The One

It has been recognized since the earliest days of crystal growth that kinetic processes of all Kinds control the nature of the growth. As the technology of crystal growth has become ever more refined, with the advent of such atomistic processes as molecular beam epitaxy, chemical vapor deposition, sputter deposition, and plasma enhanced techniques for the creation of “crystals” as little as one or a few atomic layers thick, multilayer structures, and novel materials combinations, the need to understand the mechanisms controlling the growth process is becoming more critical. Unfortunately, available techniques have not lent themselves well to obtaining a truly microscopic picture of such processes. Because of its atomic resolution on the one hand, and the achievable wide field of view on the other (of the order of micrometers) scanning tunneling microscopy (STM) gives us this opportunity. In this talk, we briefly review the types of growth kinetics measurements that can be made using STM. The use of STM for studies of kinetics is one of the more recent applications of what is itself still a very young field.

Resolution in the scanning tunneling microscope

1991 ◽  
Vol 49 ◽  
pp. 488-489
Author(s):  
R. J. Wilson ◽  
D. D. Chambliss ◽  
S. Chiang ◽  
V. M. Hallmark
Keyword(s):  
Scanning Tunneling Microscope ◽  
Fundamental Principle ◽  
Atomic Scale ◽  
Lateral Resolution ◽  
Scanning Tunneling ◽  
Electronic Noise ◽  
Vertical Resolution ◽  
Tunneling Microscopy ◽  
Spatial Profile ◽  
Theoretical Analyses

Scanning tunneling microscopy (STM) has been used for many atomic scale observations of metal and semiconductor surfaces. The fundamental principle of the microscope involves the tunneling of evanescent electrons through a 10Å gap between a sharp tip and a reasonably conductive sample at energies in the eV range. Lateral and vertical resolution are used to define the minimum detectable width and height of observed features. Theoretical analyses first discussed lateral resolution in idealized cases, and recent work includes more general considerations. In all cases it is concluded that lateral resolution in STM depends upon the spatial profile of electronic states of both the sample and tip at energies near the Fermi level. Vertical resolution is typically limited by mechanical and electronic noise.

Scanning tunneling microscopy of E. coli RNA polymerase deposited onto an Au substrate by an electrochemical process

1991 ◽  
Vol 49 ◽  
pp. 378-379
Author(s):  
Rebecca W. Keller ◽  
Carlos Bustamante ◽  
David Bear
Keyword(s):  
Scanning Tunneling Microscope ◽  
Biological Sample ◽  
Substrate Surface ◽  
Electrochemical Process ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Tunneling Microscope ◽  
E Coli ◽  
Preparation Techniques

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.

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