scholarly journals Nonzero Fermi Level Density of States for a Disorderedd-Wave Superconductor in Two Dimensions

1996 ◽  
Vol 77 (14) ◽  
pp. 3013-3016 ◽  
Author(s):  
K. Ziegler ◽  
M. H. Hettler ◽  
P. J. Hirschfeld
Keyword(s):  
Fermi Level ◽  
Density Of States ◽  
Level Density ◽  
Two Dimensions

scholarly journals Lower bound for the Fermi-level density of states of a disorderedd-wave superconductor in two dimensions

1998 ◽  
Vol 57 (17) ◽  
pp. 10825-10830 ◽  
Author(s):  
K. Ziegler ◽  
M. H. Hettler ◽  
P. J. Hirschfeld
Keyword(s):  
Lower Bound ◽  
Fermi Level ◽  
Density Of States ◽  
Level Density ◽  
Two Dimensions

Comparison of Spherical Cell, OPW, and APW Methods for Hyperfine Contact Densities

1975 ◽  
Vol 53 (6) ◽  
pp. 648-649 ◽  
Author(s):  
J. P. Perdew ◽  
S. B. Nickerson ◽  
S. H. Vosko ◽  
R. A. Moore
Keyword(s):  
Fermi Level ◽  
Density Of States ◽  
Knight Shift ◽  
Level Density ◽  
Spherical Cell ◽  
Atomic Volume ◽  
Lithium Metal ◽  
Contact Density ◽  
Absolute Value

The spherical cell, OPW, and APW methods for the determination of the direct hyperfine contact density PFd are compared by means of explicit calculations for lithium metal. Serious deficiencies of the first two methods are discussed. In particular the OPW method is found to converge very slowly for the absolute value of PFd, although it predicts relative changes in PFd due to changes in atomic volume reasonably well. The Fermi level density of states, another quantity which affects the Knight shift, is also considered.

Energetics, Electronic Properties, and Geometries of B-Doped Diamond: A First-Principles Study

2006 ◽  
Vol 956 ◽  
Author(s):  
Susumu Saito ◽  
Tomohisa Maeda ◽  
Takashi Miyake
Keyword(s):  
Fermi Level ◽  
Density Of States ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Level Density ◽  
Hole Doping ◽  
Face Centered Cubic ◽  
Geometrical Properties ◽  
Face Centered ◽  
B Doping

ABSTRACTWe study electronic and geometrical properties of B-doped diamond in the framework of the density functional theory. The systems studied are simple-cubic (sc) BC7 and face-centered-cubic (fcc) BC15 and B2C14. In the case of BC7, we also study the effect of the tetragonal and rhombohedral distortions of the unit cell to be introduced to the B-doped diamond grown homoepitaxially on the diamond (100) and (111) films, respectively. In the case of fcc B2C14, on the other hand, the inhomogeneous doping effects are discussed from the viewpoint of the energetics. It is confirmed that in the homogeneous doping case, B doping gives rise to hole doping into the valence band, which should be responsible for the metallic and superconducting transport properties of the material. In the case of the inhomogeneous doping, two B atoms on the first-nearest neighbor sites as well as on the second-nearest neighbor sites are found to lower the Fermi-level density of states, which is unfavorable for superconductivity. Although tetragonal and rhombohedral distortions are found to give a sizable change to the electronic states near the Fermi level, the value of the Fermi-level density of states itself is found to remain almost unchanged. Finally, in order to study the fundamental-gap value of the heavily B-doped diamond, we study the electronic structure of the sc BC7 and fcc BC15 in the GW approximation. A large reduction of the gap value upon doping is confirmed.

APPLICATIONS OF CLASSICAL PERIODIC ORBIT THEORY TO CIRCULAR BILLIARDS WITH SMALL SCATTERING CENTERS

1996 ◽  
Vol 03 (01) ◽  
pp. 19-23 ◽  
Author(s):  
S.M. REIMANN ◽  
M. BRACK ◽  
A.G. MAGNER ◽  
M.V.N. MURTHY
Keyword(s):  
Quantum Dots ◽  
Periodic Orbit ◽  
Density Of States ◽  
Level Density ◽  
Flux Line ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Periodic Orbit Theory ◽  
Orbit Theory

Mesoscopic systems like metallic clusters in three dimensions as well as quantum dots in two dimensions have raised a particular interest in the semiclassical interpretation of shell effects. We use periodic orbit theory to calculate the density of states for two-dimensional circular billiards. When a singular magnetic flux line is added at the center of the disk, we show that the Aharonov-Bohm (AB) effect manifests itself through the cancellation of periodic orbits and the appearance of a new signal in the Fourier transform of the quantum density of states. The same effects are also found analytically for a two-dimensional harmonic oscillator potential with flux line. Finally, we show that a homogeneous magnetic field B perpendicular to the disk plane leads to B-periodic oscillations of the level density, which recently have also been observed experimentally in two-dimensional circular quantum dots.

Annealing effect on the reduction of Fermi-level density of states in CoTiSb: NMR evidence

2009 ◽  
Vol 80 (17) ◽  
Author(s):  
C. S. Lue ◽  
C. F. Chen ◽  
Fu-Kuo Chiang ◽  
M.-W. Chu
Keyword(s):  
Fermi Level ◽  
Density Of States ◽  
Level Density ◽  
Annealing Effect
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