scholarly journals Electronic Structure of the Cubic Compounds ReGa3(Re = Er, Tm, Yb, and Lu)

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Helmut Bross
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Fermi Surface ◽  
Fermi Energy ◽  
Dielectric Response ◽  
Nuclear Charge ◽  
Dielectric Response Function ◽  
The Core ◽  
Structure Scheme ◽  
Valence Bands

The electronic structure of ErGa3and its isostructural compounds with Tm, Yb, and Lu are investigated with a highly accurate band structure scheme in LDA and GGA and warped muffin-tin approximation. In contrast to other investigations, the 4f electrons of the constituent Re are also treated as part of the valence bands. The position of the corresponding 4f bands relative to the Fermi energy strongly depends on the nuclear charge of Re. In Lu, they lie almost by 0.5 Ryd below and are extremely narrow. In Er, both in LDA and GGA, the 4f bands are found to be very close to the Fermi level . Assuming most of the 4f electrons to be part of the core removes the disagreement almost completely but produces a Fermi surface with a topology markedly different from that proposed in previous investigations. The intersections of the Fermi surface with planes are strongly varying within the Brillouin zone, they do not well match with the sparse experimental results. Investigations using the scheme as well as investigations of the dielectric response function are sketched.

The Shubnikov – de Haas effect in dilute lead-in-bismuth alloys

1968 ◽  
Vol 46 (21) ◽  
pp. 2413-2423 ◽  
Author(s):  
On-Ting Woo ◽  
R. J. Balcombe
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Carrier Concentration ◽  
Fermi Energy ◽  
Dilute Alloys ◽  
Haas Effect ◽  
Effect Of Alloying

The differential Shubnikov – de Haas effect has been studied in samples of bismuth containing up to 50 parts per million of lead. The results indicate that the only effect of alloying on the band structure of bismuth is to shift the Fermi energy; the sizes of the various pieces of the Fermi surface are changed, but their shapes are not distorted. The ratio of the change in net carrier concentration to the concentration of lead atoms is found to be only 0.4, which is anomalously low, compared with values of about 1.0 found for dilute alloys of other metals in bismuth.

scholarly journals Photoemission Spectroscopy of Single Crystal HTSC Materials: A Fermi Liquid Electronic Structure

1989 ◽  
Vol 156 ◽  
Author(s):  
A. J. Arko ◽  
R. S. List ◽  
R. J. Bartlett ◽  
S. W. Cheong ◽  
C. G. Olson ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Single Crystal ◽  
Fermi Liquid ◽  
Wide Band ◽  
Photoemission Spectroscopy ◽  
Correlation Effects ◽  
Band Dispersion ◽  
Valence Bands ◽  
Orbital Character

ABSTRACTPhotoemission spectra from HTSC materials ( primarily 123 -type ), cleaved and measured at 20K, reveal a rich DOS structure which compares favorably with a calculated band structure, except for a residual 0.5 eV shift which may reflect some correlation effects. Band dispersion is observed throughout the valence bands, with clear evidence for a 0.2 eV wide band dispersing through EF. The orbital character at EF is a mix of Cu-3d and O-2p. There is unambiguous evidence for a large BCS-like gap (2Δ≥ 4kTc).

Tight-Binding Study of the Electronic Structure of the high Temperature Superconductor La2CuO4

1987 ◽  
Vol 99 ◽  
Author(s):  
D. A. Papaconstantopoulos ◽  
M. J. Deweert ◽  
W. E. Pickett
Keyword(s):  
Electronic Structure ◽  
High Temperature ◽  
Band Structure ◽  
Fermi Surface ◽  
First Principles ◽  
High Temperature Superconductor ◽  
Tight Binding ◽  
Binding Study ◽  
Three Components

ABSTRACTWe have fit our first principles LAPW band structure results for the high Tc superconductor La2CuO4 to a tight-binding Hamiltonian that contains s, p, and d interactions from the three components of these materials. Our fit reproduces very accurately the 17 lower bands of this material and especially the Fermi surface.

Electronic Structure and Transport Properties of CoSb3: A Narrow Band-Gap Semiconductor

1998 ◽  
Vol 545 ◽  
Author(s):  
J. O. Sofo ◽  
G. D. Mahan
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Fermi Surface ◽  
Band Gap ◽  
Narrow Band ◽  
Transport Coefficients ◽  
Electronic States ◽  
Energy Bands ◽  
Effective Masses ◽  
Hall Effect Measurements

AbstractWe report calculations which show that the band structure of CoSb3 is typical of a narrow band-gap semiconductor. The gap is strongly dependent on the relative position of the Sb atoms inside the unit cell. We obtain a band gap of 0.22 eV after minimization of these position. This value is more than four times larger than the result of a previous calculation which reported that the energy bands near the Fermi surface are unusual. The electronic states close to the Fermi level are properly described by a two-band Kane Model. The calculated effective masses and band gap are in excellent agreement with Shubnikov de Haas and Hall effect measurements. Recent measurements of the transport coefficients of this compound can be understood assuming it is a narrow band gap semiconductor, in agreement with our results.

Band structure investigation of chalcopyrite CuInSe2(001) by angle-resolved photoelectron spectroscopy

2005 ◽  
Vol 865 ◽  
Author(s):  
Ralf Hunger ◽  
Christian Pettenkofer
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Bulk Composition ◽  
Synchrotron Source ◽  
Band Dispersion ◽  
Low Energy Electron ◽  
Copper Chalcopyrite ◽  
Valence Bands

AbstractClean and ordered chalcopyrite CuInSe2 surfaces are a precondition for the study of the electronic structure by angle-resolved photoelectron spectroscopy. The preparation of welldefined CuInSe2(001) surfaces by the combination of molecular beam epitaxy and a selenium capping and decapping process is described. The surface structure of CuInSe2 epilayers with different bulk composition is compared and analysed by low-energy electron diffraction.Employing near-stoichiometric surfaces, the valence electronic structure of CuInSe2 was investigated by angle-resolved photoelectron spectroscopy at the synchrotron source BESSY 2. This is the first study of the valence band structure of a copper chalcopyrite semiconductor material by photoelectron spectroscopy. The valence band dispersion along τT, i.e. the [001] direction, was investigated by a variation of the excitation energy from 10 to 35 eV under normal emission, and the band dispersion along τT, i.e. the [110] direction, was analysed by angular scans with hv = 13 eV.The valence bands derived from antibonding and bonding Se4p-Cu3d hybrid orbitals, nonbonding Cu3d states and In-Se hybrid states are clearly indentified. The strongest dispersion is found for the topmost valence band with a bandwidth of ∼0.7 eV from τ to T. From τ to N, the observed dispersion was 0.5 eV. The experimental valence bands are discussed in relation to calculated band structures in the literature.

scholarly journals Fermi surface of the skutterudite CoSb3 : Quantum oscillations and band-structure calculations

2021 ◽  
Vol 103 (8) ◽  
Author(s):  
M. Naumann ◽  
P. Mokhtari ◽  
Z. Medvecka ◽  
F. Arnold ◽  
M. Pillaca ◽  
...  
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Quantum Oscillations ◽  
Band Structure Calculations ◽  
Structure Calculations

scholarly journals The Highly Uniform Photoresponsivity from Visible to Near IR Light in Sb2Te3 Flakes

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1535
Author(s):  
Shiu-Ming Huang ◽  
Jai-Lung Hung ◽  
Mitch Chou ◽  
Chi-Yang Chen ◽  
Fang-Chen Liu ◽  
...  
Keyword(s):  
Band Structure ◽  
Energy Difference ◽  
Experimental Result ◽  
Light Illumination ◽  
Near Ir ◽  
State Band ◽  
Valence Bands ◽  
Low Dimensional ◽  
Low Dimensional Materials ◽  
Ir Light

Broadband photosensors have been widely studied in various kinds of materials. Experimental results have revealed strong wavelength-dependent photoresponses in all previous reports. This limits the potential application of broadband photosensors. Therefore, finding a wavelength-insensitive photosensor is imperative in this application. Photocurrent measurements were performed in Sb2Te3 flakes at various wavelengths ranging from visible to near IR light. The measured photocurrent change was insensitive to wavelengths from 300 to 1000 nm. The observed wavelength response deviation was lower than that in all previous reports. Our results show that the corresponding energies of these photocurrent peaks are consistent with the energy difference of the density of state peaks between conduction and valence bands. This suggests that the observed photocurrent originates from these band structure peak transitions under light illumination. Contrary to the most common explanation that observed broadband photocurrent carrier is mainly from the surface state in low-dimensional materials, our experimental result suggests that bulk state band structure is the main source of the observed photocurrent and dominates the broadband photocurrent.

Magnetic Ground State and Electronic Structure Calculations of PbMnO3 Using DFT

2014 ◽  
Vol 895 ◽  
pp. 420-423 ◽  
Author(s):  
Sathya Sheela Subramanian ◽  
Baskaran Natesan
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Fermi Level ◽  
Ground State ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Magnetic Ground State ◽  
Electronic Band ◽  
Structure Calculations ◽  
Centrosymmetric Structure

Structural optimization, magnetic ground state and electronic structure calculations of tetragonal PbMnO3have been carried out using local density approximation (LDA) implementations of density functional theory (DFT). Structural optimizations were done on tetragonal P4mm (non-centrosymmetric) and P4/mmm (centrosymmetric) structures using experimental lattice parameters and our results indicate that P4mm is more stable than P4/mmm. In order to determine the stable magnetic ground state of PbMnO3, total energies for different magnetic configurations such as nonmagnetic (NM), ferromagnetic (FM) and antiferromagnetic (AFM) were computed for both P4mm and P4/mmm structures. The total energy results reveal that the FM non-centrosymmetric structure is found to be the most stable magnetic ground state. The electronic band structure, density of states (DOS) and the electron localization function (ELF) were calculated for the stable FM structure. ELF revealed the distorted non-centrosymmetric structure. The band structure and DOS for the majority spins of FM PbMnO3showed no band gap at the Fermi level. However, a gap opens up at the Fermi level in minority spin channel suggesting that it could be a half-metal and a potential spintronic candidate.

scholarly journals Electronic Structure and the Fermi Surface ofPuCoGa5andNpCoGa5

2003 ◽  
Vol 90 (20) ◽  
Author(s):  
Takahiro Maehira ◽  
Takashi Hotta ◽  
Kazuo Ueda ◽  
Akira Hasegawa
Keyword(s):  
Electronic Structure ◽  
Fermi Surface

LCAO analysis of the electron band structure and Fermi surface of cubic superconducting perovskites

1997 ◽  
Vol 21 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Todor M. Mishonov ◽  
Ivan N. Gentchev ◽  
Radostina K. Koleva ◽  
Evgeni S. Penev
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Electron Band ◽  
Electron Band Structure
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