Critical-point study of higher conduction bands in Si single crystal by angle-resolved photoemission

1983 ◽  
Vol 28 (8) ◽  
pp. 4635-4642 ◽  
Author(s):  
A. Kasuya ◽  
Y. Nishina ◽  
T. Kobayasi
Keyword(s):  
Single Crystal ◽  
Critical Point ◽  
Conduction Bands

Preparation and Characterization of Several Conducting Transition Metal Oxides

1989 ◽  
Vol 156 ◽  
Author(s):  
Aaron Wold ◽  
Kirby Dwight
Keyword(s):  
Transition Metal ◽  
Single Crystal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Structure Property ◽  
Metallic Behavior ◽  
Structure Property Relationships ◽  
Conduction Bands ◽  
Metal Metal

ABSTRACTThe structure-property relationships of several conducting transition metal oxides, as well as their preparative methods, are presented in this paper. The importance of preparing homogeneous phases with precisely known stoichiometry is emphasized. A comparison is also made of the various techniques used to prepare both polycrystalline and single crystal samples. For transition metal oxides, the metallic properties are discussed either in terms of metal-metal distances which are short enough to result in metallic behavior, or in terms of the formation of a П* conduction band resulting from covalent metal-oxygen interactions. Metallic behavior is observed when the conduction bands are populated with either electrons or holes. The concentration of these carriers can be affected by either cation or anion substitutions. The discussion in this presentation will be limited to the elements Re, Ti, V, Cr, Mo, and Cu.

Observation of a bi-critical point between antiferromagnetic and superconducting phases in pressurized single crystal Ca 0.73 La 0.27 FeAs 2

2017 ◽  
Vol 62 (12) ◽  
pp. 857-862 ◽  
Author(s):  
Yazhou Zhou ◽  
Shan Jiang ◽  
Qi Wu ◽  
Vladimir A. Sidorov ◽  
Jing Guo ◽  
...  
Keyword(s):  
Single Crystal ◽  
Critical Point ◽  
Superconducting Phases

scholarly journals Electronic transitions and dielectric function tensor of a YMnO3 single crystal in the NIR-VUV spectral range

RSC Advances ◽  
2014 ◽  
Vol 4 (63) ◽  
pp. 33549-33554 ◽  
Author(s):  
Rüdiger Schmidt-Grund ◽  
Steffen Richter ◽  
Stefan G. Ebbinghaus ◽  
Michael Lorenz ◽  
Carsten Bundesmann ◽  
...  
Keyword(s):  
Single Crystal ◽  
Critical Point ◽  
Dielectric Function ◽  
Spectral Range ◽  
Band Gaps ◽  
Electronic Transitions ◽  
Band Absorption

The dielectric function tensor elements of an YMnO3 single crystal yield M0 critical point like band-band absorption with discrete spectrally localized Lorentzian transitions within the band gaps.

Conduction bands of GaSb

1969 ◽  
Vol 47 (3) ◽  
pp. 241-247 ◽  
Author(s):  
Eric H. van Tongerloo ◽  
John C. Woolley
Keyword(s):  
Single Crystal ◽  
Faraday Rotation ◽  
Room Temperature ◽  
Free Carrier ◽  
Temperature Data ◽  
Energy Separation ◽  
Mass Ratio ◽  
Scattering Parameter ◽  
Conduction Bands ◽  
Effective Mass Ratio

Room temperature measurements of free-carrier Faraday rotation have been made on four different single-crystal n-type tellurium-doped samples of GaSb which had been used previously in magnetoresistance measurements. From the combined results for each specimen, values have been calculated for the energy separation of the (000) and [Formula: see text] conduction band minima, ΔE, and the transverse effective-mass ratio of the [Formula: see text] electrons, m1t/m. It is found that ΔE is a function of tellurium content. The value of ΔE at 4.2 °K for an intrinsic sample is hence found to be 0.078 eV. The values obtained for m1t/m, the variation of ΔE with tellurium content (dΔE/dy), and the temperature coefficient of ΔE (dΔE/dT) depend upon the value of the scattering parameter s assumed in the analysis of the room-temperature data. It is shown that the correct value of s lies in the range 0.5 to 1.0 and this gives values for m1t/m = 0.110 and dΔEdy = 0.50 eV/atomic % Te, while dΔE/dT probably lies in the range 0 to −2 × 10−5 eV/°K.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

SEM Cold Stage Techniques for the Observation of Vegetative and Floral Apices of Oat (Avena sativa L.) Plants

1977 ◽  
Vol 35 ◽  
pp. 590-591
Author(s):  
B. K. Kirchoff ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Critical Point ◽  
Avena Sativa ◽  
Substantial Improvement ◽  
Fresh Tissue ◽  
Cold Stage ◽  
Critical Point Drying ◽  
Almost All ◽  
Cell Collapse ◽  
Conductive Paint ◽  
Carbon Based

In attempting to use the SEM to investigate the transition from the vegetative to the floral state in oat (Avena sativa L.) it was discovered that the procedures of fixation and critical point drying (CPD), and fresh tissue examination of the specimens gave unsatisfactory results. In most cases, by using these techniques, cells of the tissue were collapsed or otherwise visibly distorted. Figure 1 shows the results of fixation with 4.5% formaldehyde-gluteraldehyde followed by CPD. Almost all cellular detail has been obscured by the resulting shrinkage distortions. The larger cracks seen on the left of the picture may be due to dissection damage, rather than CPD. The results of observation of fresh tissue are seen in Fig. 2. Although there is a substantial improvement over CPD, some cell collapse still occurs.Due to these difficulties, it was decided to experiment with cold stage techniques. The specimens to be observed were dissected out and attached to the sample stub using a carbon based conductive paint in acetone.

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