Electronic structure study of new family of high-Tc Fe-superconductors based on BaFe2As2 in presence of dopants Rh and Pd.

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3365-3372
Author(s):  
Ronald Columbié-Leyva ◽  
Jacques Soullard ◽  
Ilya G. Kaplan
Keyword(s):  
Spin Density ◽  
Electron Correlation ◽  
Population Analysis ◽  
Ferromagnetic State ◽  
Structure Study ◽  
Cluster Method ◽  
High Tc ◽  
New Family ◽  
Correlation Level ◽  
Density Transfer

AbstractThe superconductivity has a long history. One of the most recent discoveries is the superconductivity in the Fe- based family with anti- ferromagnetic state at ambient temperature. In this type of material, the transition to the superconductivity state was found in presence of different dopants. In this report we present the results of calculations of the cluster representing Ba4Fe5As8 in presence of Rh and Pd as dopants. The methodology of Embedded Cluster Method at the MP2 electron correlation level was employed. The population analysis showed two main features: the independence of charge density transfer from the spin density transfer and, the presence of orbitals with electron density but without spin density. The observed properties correspond to the RVB mechanism for the superconductivity transition proposed by Anderson for cuprates. This confirms our conclusions obtained in the same material doped by Co and Ni.

Fe-family of superconductors: Influence of Ni dopant on the superconductivity in BaFe2As2 crystal and the relaxation volume

MRS Advances ◽  
2019 ◽  
Vol 4 (55-56) ◽  
pp. 3069-3076
Author(s):  
Jacques Soullard ◽  
Ilya G. Kaplan
Keyword(s):  
Electron Correlation ◽  
Population Analysis ◽  
Atomic Orbital ◽  
Cluster Method ◽  
Unconventional Superconductivity ◽  
Electronic Density ◽  
Orbital Population ◽  
Moller Plesset ◽  
Correlation Level ◽  
Plesset Perturbation Theory

ABSTRACTThe doped iron arsenides present outstanding properties, one of them is an unconventional superconductivity, an unusual coexistence of superconductivity and magnetism. We calculated the electronic structure of the pure and Ni-doped BaF e2As2 by the embedded cluster method at the electron correlation level; the latter is calculated through the second- order Møller Plesset perturbation theory. For the doped clusters, we calculated the relaxation of the first and second neighbors of the impurity by optimizing their positions in the cluster. The total electronic density is analyzed through natural bond orbitals and the population of each atomic orbital (basis function) is determined; the robustness of this determination is tested comparing results obtained for the unrelaxed and relaxed cluster. The orbital population analysis uncovers some properties of magnetism and superconductivity in BaFe2As2. From our results, linear elasticity allows us to estimate the relaxation volume of Ni impurity.

Unconventional density wave in the pseudogap phase of high Tc cuprates

2002 ◽  
Vol 12 (9) ◽  
pp. 45-48
Author(s):  
K. Maki ◽  
B. Dora ◽  
A. Virosztek
Keyword(s):  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
High Tc ◽  
Pseudogap Phase ◽  
High Tc Cuprates ◽  
Optical Dichroism

We propose here that the pseudogap phase of high Tc superconductors is probably unconventional spin density wave (USDW). We present our analysis on the angular dependent magnetoresistance (ADMR) in the pseudogap phase which should be accessible experimentally. Also this result applies also to the AF phase of URu2Si2. We show that this model is consistent with the optical dichroism seen by ARPES.

Spin density transfer from guest to host in endohedral heterofullerene dimers

2019 ◽  
Vol 21 (14) ◽  
pp. 7605-7612
Author(s):  
Vinit Vinit ◽  
C. N. Ramachandran
Keyword(s):  
Density Functional Theory ◽  
Spin Density ◽  
Density Functional ◽  
Functional Theory ◽  
Density Transfer

The endohedral heterofullerenes (B@C59B)2, (B@C59N)2, (N@C59B)2 and (B@C59N–N@C59B) are investigated using dispersion corrected density functional theory.

scholarly journals Electron correlation and two dimensionality in the spin-density-wave phase of(TMTTF)2Brunder pressure

2003 ◽  
Vol 67 (21) ◽  
Author(s):  
A. Ishikawa ◽  
N. Matsunaga ◽  
K. Nomura ◽  
T. Sasaki ◽  
T. Nakamura ◽  
...  
Keyword(s):  
Spin Density ◽  
Electron Correlation ◽  
Density Wave ◽  
Spin Density Wave ◽  
Wave Phase

Spin density in the high Tc superconductor YBa2Cu3O7

1992 ◽  
Vol 104-107 ◽  
pp. 630-632 ◽  
Author(s):  
J.X. Boucherle ◽  
J.Y. Henry ◽  
R. Papoular ◽  
J. Rossat-Mignod ◽  
J. Schweizer ◽  
...  
Keyword(s):  
Spin Density ◽  
High Tc ◽  
High Tc Superconductor

Tuning of Spin Density Wave Strengths in Quasi-One-Dimensional Mixed-Halogen-Bridged Nickel(III) Complexes with Strong Electron Correlation, [NiIII(chxn)2Cl1-xBrx](NO3)2

2002 ◽  
Vol 41 (20) ◽  
pp. 4993-4995 ◽  
Author(s):  
Toshio Manabe ◽  
Kohei Yokoyama ◽  
Sachie Furukawa ◽  
Chihiro Kachi-Terajima ◽  
Kazuya Nakata ◽  
...  
Keyword(s):  
Spin Density ◽  
Electron Correlation ◽  
Density Wave ◽  
Spin Density Wave ◽  
Strong Electron Correlation ◽  
Strong Electron ◽  
One Dimensional

ATOMIC STRUCTURE STUDY OF THE Ag/MgO(100) SURFACE BY AN AB INITIO, TOTAL ENERGY MOLECULAR CLUSTER METHOD USING DENSITY FUNCTIONAL THEORY

1996 ◽  
Vol 03 (03) ◽  
pp. 1365-1375 ◽  
Author(s):  
LAURENT SPIESS
Keyword(s):  
Density Functional Theory ◽  
Total Energy ◽  
Ab Initio ◽  
Density Functional ◽  
Structure Study ◽  
Cluster Method ◽  
Molecular Cluster ◽  
Functional Theory ◽  
Molecular Systems ◽  
Coverage Dependence

The clean and Ag-covered MgO(100) surface is investigated by an all-electron, total energy, ab initio DMol molecular method (Density functional theory for Molecular systems). A large cluster of 100 atoms (including 50 oxygen and 50 magnesium) is built to represent the surface. A point charge embedding is used to investigate the electronic properties. The small relaxation of the surface, referred to as rumpling, is exhibited and shown to have barely no effect on the adsorption of Ag on the surface. The oxygen site is found to be the most stable for Ag atom adsorption, in good agreement with previous ab initio theoretical studies. The adsorption of a five-Ag-atom layer on the MgO(100) surface provides new and interesting results concerning the surface coverage dependence. We have used the unique ability of cluster methods to study the structural effects of the 3% mismatch at the Ag/MgO(100) interface, and we show that Ag atoms are likely to grow on the surface without epitaxy at low coverages.

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