Elastic Instability of the Orthorhombic Antiferromagnetic Phase of 122-Pnictides Under Pressure

Widom, Michael; Quader, Khandker

doi:10.1007/s10948-015-3324-y

Cited by 2 publications

(2 citation statements)

References 29 publications

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“…These effects might be responsible for the huge magneto-elastic coupling to the As-derived A 1g phonon mode in and near the regions of coexistence between magnetism and superconductivity, showing in particular a large deformation potential of about 0.1-0.15 eV nm −1 in the parent compound BaFe 2 As 2 [46], and the observation of magneto-elastic coupling for Ba(Fe 1−x Co x ) 2 As 2 , even at room temperature [47] (see also Refs. [40,48,49]) . Several observed phonon anomalies [50][51][52] also point to significant couplings between the lattice and the charge, spin, or orbital degrees of freedom.…”

Section: General Aspects Of El-el Interactionsmentioning

confidence: 99%

Constraints on the total coupling strengthto bosons in the iron based superconductors

Drechsler

Johnston

Grinenko

et al. 2017

Phys. Status Solidi B

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Despite the fact that the Fe-based superconductors (FeSCs) were discovered nearly ten years ago, the community is still devoting a tremendous effort towards elucidating their relevant microscopic pairing mechanism(s) and interactions. At present, there is still no consistent interpretation of their normal state properties, where the strength of the electron-electron interaction and the role of correlation effects are under debate. Here, we examine several common materials and illustrate various problems and concepts that are generic for all FeSCs. Based on empirical observations and qualitative insight from density functional theory, we show that the superconducting and low-energy thermodynamic properties of the FeSCs can be described semi-quantitively within multiband Eliashberg theory. We account for an important high-energy mass renormalization phenomenologically, and in agreement with constraints provided by thermodynamic, optical, and angle-resolved photoemission data. When seen in this way, all FeSCs with T c < 40 K studied so far are found to belong to an intermediate coupling regime. This finding is in contrast to the strong coupling scenarios proposed in the early period of the FeSC history. We also discuss several related issues, including the role of band shifts as measured by the positions of van Hove singularities, and the nature of a recently suggested quantum critical point in the strongly hole-doped systems AFe 2 As 2 (A = K, Rb, Cs). Using high-precision full relativistic GGA-band structure calculations, we arrive at a somewhat milder mass renormalization in comparison with previous studies. From the calculated mass anisotropies of all Fermi surface sheets, only the ε-pocket near the corner of the BZ is compatible with the experimentally observed anisotropy of the upper critical field, pointing to its dominant role in the superconductivity of these three compounds.

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Section: General Aspects Of El-el Interactionsmentioning

confidence: 99%

Constraints on the total coupling strengthto bosons in the iron based superconductors

Drechsler

Johnston

Grinenko

et al. 2017

Phys. Status Solidi B

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“…Complexity and phase separation scenarios in complex oxides and functional strongly correlated systems have recently attracted a wide interest [53][54][55][56][57][58][59][60][61][62][63]. Iron-based superconductors have provided a key laboratory showing exotic superconducting phases characterized by inhomogeneity, nematic phases and multiple gaps [64][65][66][67][68][69]. The physics of the BCS-BEC crossover in quantum condensates in particular real space or k space spots widely studied in ultracold gases is now emerging as a generic feature in multiple condensates superconductors [70][71][72][73][74][75][76].…”

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confidence: 99%

Complex Lattice and Charge Inhomogeneity Favoring Quantum Coherence in High-Temperature Superconductors

Bianconi

2016

J Supercond Nov Magn

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The presence of two components in the electron fluid of high temperature superconductors and the complex charge and lattice inhomogeneity have been the hot topics of the international conference of the superstripes series, Superstripes 2015, held in Ischia in 2015. The debate on the mechanisms for reaching room temperature superconductors has been boosted by the discovery of superconductivity with the highest critical temperature in pressurized sulfur hydride. Different complex electronic and structural landscapes showing up in superconductors, which resist to the decoherence effects of high temperature, have been discussed. While low temperature superconductors described by the BCS approximation are made of a single condensate in the weak coupling the high temperature superconductors are made of coexisting multiple condensates (in different spots of the k--space and the real space) some in the BCS--BEC crossover regime and others in the BCS regime. The role of "shape resonance" in the exchange interaction between these different condensates, like "the Fano--Feshbach resonance" in ultracold gasses, is emerging as a key term for high temperature superconductivity.

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Elastic Instability of the Orthorhombic Antiferromagnetic Phase of 122-Pnictides Under Pressure

Cited by 2 publications

References 29 publications

Constraints on the total coupling strengthto bosons in the iron based superconductors

Constraints on the total coupling strengthto bosons in the iron based superconductors

Complex Lattice and Charge Inhomogeneity Favoring Quantum Coherence in High-Temperature Superconductors

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