Structural and electronic properties of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Y</mml:mi><mml:msub><mml:mi mathvariant="normal">Ba</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">Cu</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml

Khosroabadi, H.; Mossalla, B.; Akhavan, M.

doi:10.1103/physrevb.70.134509

Cited by 20 publications

(14 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The similar results also were obtained by the calculations with ionic model and first-principle method. [11][12][13] Additionally, using the pseudopotential density functional theory, Khosroabadi 14 calculated the structural and electronic properties of two YBCO and YSCO, and demonstrated that the electronic charge density distribution was reduced in both CuO 2 planes and Cu-O chains with an increase of external pressure on the superconductors.…”

Section: Introductionmentioning

confidence: 99%

Pressure induced self-doping and dependence of critical temperature in stoichiometry YBa2Cu3O6.95 predicted by first-principle and BVS calculations

2017

View full text Add to dashboard Cite

This paper deals with the pressure effect on self-doping and critical temperature in optimum oxygen stoichiometry YBa2Cu3O6.95 of high temperature superconductor (HTS) based on a numerical study combined the first-principle with bond valence sum (BVS) calculations. The microscopic electronic properties and equilibrium ionic position configurations in the superconductor under external pressure are firstly calculated using the first-principle method. The results show that the apex oxygen in the cuprate superconductor shifts towards CuO2 plane due to pressure effect, and the minimum buckling angle of CuO2 plane is correlated with the maximum critical temperature. A BVS formalism is then utilized for evaluating the valences of all ions in the superconductor on the basis of the electronic and ionic properties and the hole concentration in both CuO2 plane and Cu-O chain are deduced. It demonstrates that the pressure-induced charge redistribution leads to a self-doping process of the hole-transfer into CuO2 plane from both Cu-O chain and Y site in the cuprate superconductor, which is the dominant mechanism of pressure effect on the superconductive properties. In order to quantitatively predict critical temperature profile of YBa2Cu3O6.95 under pressure, a modified formula describing pressure-induced charge transfer taking into account pressure dependence of the optimum hole concentration is developed. The predicted results exhibit good agreements with the experimental data in the literature, and the model parameters on the critical characteristics of the superconductor are discussed in details.

show abstract

Section: Introductionmentioning

confidence: 99%

Pressure induced self-doping and dependence of critical temperature in stoichiometry YBa2Cu3O6.95 predicted by first-principle and BVS calculations

2017

View full text Add to dashboard Cite

show abstract

“…Density-functional theory (DFT) has shown 18,19 its ability to reproduce the groundstate atomic structure of YBCO within its typical error < 3%. However, DFT does not describe excited states.…”

Section: Introductionmentioning

confidence: 99%

Screening inYBa2Cu3O7−δat large wave vectors

et al. 2010

View full text Add to dashboard Cite

We present experimental inelastic x-ray scattering (IXS) and ab initio time-dependent densityfunctional-theory (TDDFT) studies of YBa2Cu3O 7−δ . The response of the low-lying Ba 5p and Y 4p core electrons is shown to interact strongly with the Cu 3d and O 2p excitations, with important consequences on screening. The agreement between IXS and TDDFT results is excellent, apart from a new type of excitations, mainly related to loosely bound Ba electrons and significantly affected by correlations. This points to correlation mechanisms not fully described by TDDFT that might have a role in giving rise to antiscreening.

show abstract

“…Comparing these data with experimental data shows that the computational data for all of lattice parameters is about 1.14 % lower than the experimental data. These values for volumes are about 3.5 % and 3.4 % lower than the experimental values for the Y123 and Y124, respectively and are in the range of computational studies [9,11] Tables 1 and 2 for Y123 and Y124 systems, respectively. The calculated eigenvalues and eigenvectors are in good agreement with other computational studies and the eigenvalues are about 10 percent bellow the reported Raman data [8].…”

mentioning

confidence: 84%

“…Previous studies [8,9] indicate that performing LDA calculations in the experimental volume unit cell give the eigenvalues 10 percent below the experimental data, while, doing the calculation in optimized unit cell would improve them [8]. Detail description of each mode will be published elsewhere [14].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Coupling of the electronic band structure with A_g phonon modes in Y123 and Y124 systems

Khosroabadi

Mossalla

Akhavan

2006

Phys. Status Solidi (c)

Self Cite

View full text Add to dashboard Cite

Ab initio frozen-phonon calculations have been performed for k = 0 A g Raman modes of two superconducting systems Y123 and Y124. We have used the local density approximation pseudopotential method in our calculations by VASP code. Results have been compared with other computational and experimental data for similar systems. Then we present changes of electronic band structure with the change of ionic positions in each A g mode for both systems. [3] studies indicate that the electronphonon interaction has an important role in the mechanism of superconductivity of cuprate oxide high temperature superconductors (HTSCs) while early belief was the most importance of the electronelectron interaction [4,5]. Photoemission experiments [1] show a large kink in the hole dispersion at about 70 meV binding energy, suggesting a strong coupling of holes with a bosonic mode with 70 meV energy. A computational study in the t-J model indicates that the strong distance dependence of the hopping and Coulomb integrals results in a strong electron-phonon coupling and explains the softening of half-breathing phonon mode [6]. Some computational studies indicate that the renormalization of electron-phonon interaction by the electronic correlations could explain the anomalous behavior of different transport experiments and introduce a large coupling constant for producing high superconducting transition temperature [7].To clear the relative importance of electron phonon interaction in HTSCs, we have investigated the effect of A g Raman modes on the electronic band structure (EBS). In this study, we have calculated the eigenvalues and eigenvectors of A g Raman modes of YBa 2 Cu 3 O 7 (Y123) and YBa 2 Cu 4 O 8 (Y124) systems based on density functional theory in the local density approximation (LDA). This is a conventional approach to calculate structural and vibrational properties of HTSCs, even in the strong correlation regime where EBS calculations have some overestimations [8]. Then, the results of EBS calculation in each bare mode and their coupling with each mode have been explained.

show abstract

Structural and electronic properties ofYBa2Cu3O7and

Cited by 20 publications

References 42 publications

Pressure induced self-doping and dependence of critical temperature in stoichiometry YBa2Cu3O6.95 predicted by first-principle and BVS calculations

Pressure induced self-doping and dependence of critical temperature in stoichiometry YBa2Cu3O6.95 predicted by first-principle and BVS calculations

Screening inYBa2Cu3O7−δat large wave vectors

Coupling of the electronic band structure with A_g phonon modes in Y123 and Y124 systems

Contact Info

Product

Resources

About

Structural and electronic properties ofYBa2Cu3O7and

Cited by 20 publications

References 42 publications

Pressure induced self-doping and dependence of critical temperature in stoichiometry YBa2Cu3O6.95 predicted by first-principle and BVS calculations

Pressure induced self-doping and dependence of critical temperature in stoichiometry YBa2Cu3O6.95 predicted by first-principle and BVS calculations

Screening inYBa2Cu3O7−δat large wave vectors

Coupling of the electronic band structure with Ag phonon modes in Y123 and Y124 systems

Contact Info

Product

Resources

About

Coupling of the electronic band structure with A_g phonon modes in Y123 and Y124 systems