Dynamical coherent-potential approximation approach to excitation spectra in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>3</mml:mn><mml:mi>d</mml:mi></mml:mrow></mml:math>transition metals

Kakehashi, Y.; Patoary, M. Atiqur R.; Tamashiro, Toshihito

doi:10.1103/physrevb.81.245133

Cited by 17 publications

(25 citation statements)

References 74 publications

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“…It is seen that for all the investigated alloys a new absorption band with a maximum at 2.05…2.15 eV appears. From the obtained data presented in Figs 3 and 4, the following conclusions can be made: first, at low concentrations of Mn (5%) it solves almost completely [11] and Cu-Mn alloys within the impurity band (dashed lines).…”

Section: Resultsmentioning

confidence: 70%

“…Intense interband absorption is observed above the absorption edge, which is associated with transitions in the large volume of BZ from 2-nd, 3-rd and 4-th bands into the free states of the sixth band in W L  and X D  directions of the Brillouin zone [10]. Taking into account that the high-energy peak in the σ(hν) curve of copper at 4.7 eV is related to transitions from the sixth to the seventh band, mainly from d-states of L 1 to free sp-band levels of 2 L [11], one arrives to conclusion that the structure of d-bands located at 4.0…4.95 eV lower than the Fermi level is not changed in the alloys and is similar to the d-bands of copper. Thus, the energy bands in the investigated Cu-Mn alloys retain the characteristics of the electron spectrum inherent to pure copper.…”

Section: Resultsmentioning

confidence: 99%

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Optical and electronic properties of Cu-Mn solid solutions

Бондар¹

2013

Semicond. Phys. Quantum Electron. Optoelectron.

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The optical properties of Cu-Mn alloys with Mn concentrations of 2, 5, 10 and 17.5% (which corresponds to the γ-solid solutions) were studied within a wide spectral range of 0.23 to 2.8 μm (0.44…5.39 eV). Real and imaginary parts of the refractive index were measured, other optical properties such as dielectric constant, optical conductivity and the coefficient of specular reflectance at normal incidence were calculated being based on them. The analysis of the dispersion dependences ε(h), R(h) and h) enabled us to offer the electronic structure model for these alloys. According to this model, the electronic spectra (dependence of the density of electronic states on energy N(E)) of alloys with the indicated concentrations of components are the superposition of electronic spectra of Cu host, with weights equal to Cu concentrations, and the density of states within the impurity band, calculated using the experimental data.

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Section: Resultsmentioning

confidence: 70%

Section: Resultsmentioning

confidence: 99%

Optical and electronic properties of Cu-Mn solid solutions

Бондар¹

2013

Semicond. Phys. Quantum Electron. Optoelectron.

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“…The atomic level ǫ 0 L is calculated from the LDA atomic level ǫ L by subtracting the d-d Coulomb potential contribution. 21,23 The third term at the rhs (right-hand-side) of Eq. (1) denotes the on-site Coulomb interactions between d electrons.…”

Section: First-principles Mlamentioning

confidence: 99%

“…Alternative approach to quantitative description of correlated electrons is the first-2/18 principles DMFT (DCPA) combined with the LDA+U Hamiltonian. [20][21][22][23][24][25] The LDA+DMFT is a powerful method to strongly correlated electrons and has been applied to many systems.…”

Section: Introductionmentioning

confidence: 99%

First-Principles Momentum Dependent Local Ansatz Approach to the Ground-State Properties of Iron-Group Transition Metals

Kakehashi

Chandra

2016

J. Phys. Soc. Jpn.

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The ground-state properties of iron-group transition metals from Sc to Cu have been investigated on the basis of the first-principles momentum dependent local ansatz (MLA) theory. Correlation energy gain is found to show large values for Mn and Fe: 0.090 Ry (Mn) and 0.094 Ry (Fe). The Hund-rule coupling energies are found to be 3000 K (Fe), 1400 K (Co), and 300 K (Ni). It is sugested that these values can resolve the inconsistency in magnetic energy between the density functional theory and the first-principles dynamical coherent potential approximation theory at finite temperatures. Charge fluctuations are shown to be suppressed by the intra-orbital correlations and inter-orbital charge-charge correlations, so that they show nearly constant values from V to Fe: 1.57 (V and Cr), 1.52 (Mn), and 1.44 (Fe), which are roughly twice as large as those obtained by the d band model. The amplitudes of local moments are enhanced by the intra-orbital and inter-orbital spin-spin correlations and show large values for Mn and Fe: 2.87 (Mn) and 2.58 (Fe). These values are in good agreement with the experimental values estimated from the effective Bohr magneton number and the inner core photoemission data. KEYWORDS: first-principles variational theory, momentum-dependent local ansatz, iron-group transition metals, electron correlations, correlation energy, charge fluctuations, amplitude of local moment * yok@sci.u-ryukyu.ac.jp, to be published in J. Phys. Soc. Jpn. 85 (2016).

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“…We remark that the first-principles MLA is competitive with the first-principles DMFT (i.e., DCPA) 3,[21][22][23][24][25] for the calculation of the properties at zero temperature. The DMFT is a powerful method to strongly correlated electrons and has been applied to many systems.…”

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confidence: 99%

First-Principles Momentum Dependent Local Ansatz Approach to the Momentum Distribution Function in Iron-Group Transition Metals

Kakehashi

Chandra

2017

J. Phys. Soc. Jpn.

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The momentum distribution function (MDF) bands of iron-group transition metals from Sc to Cu have been investigated on the basis of the first-principles momentum dependent local ansatz wavefunction method. It is found that the MDF for d electrons show a strong momentum dependence and a large deviation from the Fermi-Dirac distribution function along high-symmetry lines of the first Brillouin zone, while the sp electrons behave as independent electrons. In particular, the deviation in bcc Fe (fcc Ni) is shown to be enhanced by the narrow e g (t 2g ) bands with flat dispersion in the vicinity of the Fermi level. Mass enhancement factors (MEF) calculated from the jump on the Fermi surface are also shown to be momentum dependent. Large mass enhancements of Mn and Fe are found to be caused by spin fluctuations due to d electrons, while that for Ni is mainly caused by charge fluctuations. Calculated MEF are consistent with electronic specific heat data as well as the recent angle resolved photoemission spectroscopy data.

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Dynamical coherent-potential approximation approach to excitation spectra in3dtransition metals

Cited by 17 publications

References 74 publications

Optical and electronic properties of Cu-Mn solid solutions

Optical and electronic properties of Cu-Mn solid solutions

First-Principles Momentum Dependent Local Ansatz Approach to the Ground-State Properties of Iron-Group Transition Metals

First-Principles Momentum Dependent Local Ansatz Approach to the Momentum Distribution Function in Iron-Group Transition Metals

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