Influence of multi-orbital hopping and anisotropy in intra and inter orbital Coulomb interactions on the electronic spectra in iron pnictide superconductors

Rani, Luxmi; Ajay, Ajay

doi:10.1016/j.physc.2015.01.003

Cited by 3 publications

(6 citation statements)

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“…Figure 1 shows the possible hopping parameters existing among d xz , d yz, and d xy orbitals. [ 43 ] The nearest neighbor hopping between σ‐orbitals of d xz and d yz is shown by t 1 parameter and between π ‐orbitals of d xz and d yz is presented by t 2 . The second nearest neighbor hopping between similar orbitals d xz and d yz is shown by t 3 and between different orbitals of d xz /d yz is presented by t 4 .…”

Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

“…To study the specific heat as a function of various orbital hopping parameters, the following six coupled Green's function equations within BCS mean‐field approximation have been developed in the situation where J H may provide an order parameter that can be treated as a PG parameter (

Δ_{normalH} = Δ_{PG}

) due to anti‐ferromagnetic ordered background in Fe‐3 d orbitals. [ 41,43 ] Therefore

false{ω - false(ε_{1 k} + U^{'} ⟨ n_{1} ⟩ + U^{″} ⟨ n_{2} ⟩ false) false} {⟨ ⟨ C_{1 k σ} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω} = \frac{1}{2 π} + ε_{12 k} {⟨ ⟨ C_{2 k σ} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω} + (Δ_{k 11} + Δ_{PG 22}) {⟨ ⟨ C_{1 - k - σ}^{+} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω}

false{ω + false(ε_{1 k} + U^{'} ⟨ n_{1} ⟩ + U^{″} ⟨ n_{2} ⟩ false) false} {⟨ ⟨ C_{1 - k - σ}^{+} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω} = (Δ_{k 11}^{+} + Δ

…”

Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

“…[4,7,46] Figure 1 shows the possible hopping parameters existing among d xz , d yz, and d xy orbitals. [43] The nearest neighbor hopping between σ-orbitals of d xz and d yz is shown by t We start with the kinetic part of the model Hamiltonian by taking into account three orbitals per site on the 2D square lattice of Fe applicable for iron pnictides. [7,8] Thus, the kinetic part is written as follows…”

Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

“…To study the specific heat as a function of various orbital hopping parameters, the following six coupled Green's function equations within BCS mean-field approximation have been developed in the situation where J H may provide an order parameter that can be treated as a PG parameter (Δ H ¼ Δ PG ) due to anti-ferromagnetic ordered background in Fe-3d orbitals. [41,43] Therefore…”

Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

“…[41] Previously, we have studied and numerically analyzed the electronic states and isotope effect in iron pnictides within two orbital per site model as a function of various model parameters within the BCS framework, using Green's function formalism. [42][43][44] In the present work, we consider the three-orbital analysis along with the incorporation of PG arising out of Hund's coupling parameter to investigate specific heat variations in ironpnictide systems. In the next section, the model of the Hamiltonian and theoretical formalism of the current work are described.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High T_c Superconductors

Ahalawat

Rani

Ajay

2022

Physica Status Solidi (b)

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A three‐orbital per site theoretical model study is attempted to analyze the nature of specific heat in iron‐based superconductors. Based on recent experimental data, it is found that the five Fe 3d orbitals, Hund's coupling, and intra‐ and inter‐electron orbital correlations play a significant role in the electronic properties of these systems. Thus, in the present work, a model Hamiltonian containing hopping between orbitals, Hund's coupling, and intra‐ and inter‐orbital Coulomb interactions is employed for iron pnictide. Employing Green's function technique within Bardeen–Cooper–Schrieffer (BCS) mean‐field approximation, expressions of superconducting energy gap parameter and quasiparticle energies are obtained. Considering these parameters, specific heat is calculated and its variation with temperature and other parameters of the model Hamiltonian is analyzed. Also, a pseudogap (PG) parameter, arising out of multi‐orbitals’ Hund's coupling, as supported by angle‐resolved photoemission spectroscopy and scanning tunneling microscopy experiments, is introduced. The expression of specific heat is numerically analyzed to pinpoint its variation below and above the transition temperature (T c). Self‐consistent numerical analysis of the specific heat jump as a function of multi‐orbital hopping, electron interactions, and Hund's coupling in terms of PG parameter is shown in detail. Finally, the outcomes are compared with recent theoretical and experimental data available on specific heat variations in iron superconductors like LaOFeAs system.

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Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

Δ_{normalH} = Δ_{PG}

) due to anti‐ferromagnetic ordered background in Fe‐3 d orbitals. [ 41,43 ] Therefore

false{ω - false(ε_{1 k} + U^{'} ⟨ n_{1} ⟩ + U^{″} ⟨ n_{2} ⟩ false) false} {⟨ ⟨ C_{1 k σ} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω} = \frac{1}{2 π} + ε_{12 k} {⟨ ⟨ C_{2 k σ} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω} + (Δ_{k 11} + Δ_{PG 22}) {⟨ ⟨ C_{1 - k - σ}^{+} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω}

false{ω + false(ε_{1 k} + U^{'} ⟨ n_{1} ⟩ + U^{″} ⟨ n_{2} ⟩ false) false} {⟨ ⟨ C_{1 - k - σ}^{+} false| C_{1 k σ}^{+} ⟩ ⟩}_{ω} = (Δ_{k 11}^{+} + Δ

…”

Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

Section: Model Hamiltonian and Theoretical Formalismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High T_c Superconductors

Ahalawat

Rani

Ajay

2022

Physica Status Solidi (b)

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Influence of multiorbital and anisotropic Coulomb interactions on isotope effect coefficient in doped Fe-based superconductors

Rani

Ajay

2017

Physica C: Superconductivity and its Applications

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Theoretical Study on the Effect of Multiband Structure on Critical Temperature and Electronic Specific Heat in SmOFeAs Iron Pnictide Superconductor

Masih¹,

Masih²,

Khandka³

2022

JAMP

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In the present theoretical work, superconducting order parameter (∆) and electronic specific heat (C es ) of SmOFeAs iron pnictide (IP) superconductor has been studied using multiband (MB) model of IP superconductors. Attempt has been made to use the MB structure of IP superconductors and expressions for critical temperature (T c ) and C es are obtained, calculations being made for one, two and three bands of SmOFeAs. It has been found that MB results are close to the experimental value of T c for this compound. C es calculations show jump of 1.5 × 10 −5 eV/atom K, 4 × 10 −5 eV/atom K and 4 × 10 −5 eV/atom K for one, two and three band models respectively. The study brings out the importance of MB structure in IPs, highlighting the fact that increasing the number of bands, increases T c . The specific heat jump (∆C) does not correspond to the BCS value, thereby proving that IPs are unconventional in nature.

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Influence of multi-orbital hopping and anisotropy in intra and inter orbital Coulomb interactions on the electronic spectra in iron pnictide superconductors

Cited by 3 publications

References 50 publications

Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High T_c Superconductors

Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High T_c Superconductors

Influence of multiorbital and anisotropic Coulomb interactions on isotope effect coefficient in doped Fe-based superconductors

Theoretical Study on the Effect of Multiband Structure on Critical Temperature and Electronic Specific Heat in SmOFeAs Iron Pnictide Superconductor

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Influence of multi-orbital hopping and anisotropy in intra and inter orbital Coulomb interactions on the electronic spectra in iron pnictide superconductors

Cited by 3 publications

References 50 publications

Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High Tc Superconductors

Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High Tc Superconductors

Influence of multiorbital and anisotropic Coulomb interactions on isotope effect coefficient in doped Fe-based superconductors

Theoretical Study on the Effect of Multiband Structure on Critical Temperature and Electronic Specific Heat in SmOFeAs Iron Pnictide Superconductor

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Product

Resources

About

Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High T_c Superconductors

Influence of Multi‐Orbitals and Hund's Coupling Induced Pseudogap on Specific Heat Jump in Iron‐Pnictide High T_c Superconductors