Strong spin resonance mode associated with suppression of soft magnetic ordering in hole-doped Ba1-xNaxFe2As2

Waßer, F.; Park, J. T.; Aswartham, Saicharan; Wurmehl, S.; Sidis, Y.; Steffens, P.; Schmalzl, K.; Büchner, B.; Braden, M.

doi:10.1038/s41535-019-0198-4

Cited by 9 publications

(6 citation statements)

References 56 publications

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“…The c-axis dispersion of SRM can be quantitatively described by the bandwidth E = E even − E odd , namely, the peak energy difference between even and odd Ls [36]. To compare with different systems near the optimal doping level, we have normalized E by k B T c , and then plot it versus d for all available data in iron-pnictide superconductors [24][25][26][29][30][31][32][34][35][36][37][38][39][40][41]. As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Interlayer coupling in the superconducting state of iron-based superconductors

Hong

Zhou

et al. 2023

Phys. Rev. B

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High-temperature superconducting paring is generally believed to be mediated by the magnetic fluctuations that mostly occur within the two-dimensional conducting layers (Cu-O, Fe-As, or Fe-Se) in copper oxides, iron pnictides, iron chalcogenides, etc. Here, on the basis of inelastic neutron scattering measurements on a superconducting iron pnictide Ca 0.33 Na 0.67 Fe 2 As 2 , we have discovered a highly three-dimensional spin resonance mode with upward V-shape dispersions both in the ab plane and along the c axis. The superconducting gaps exhibit strong k z modulations involved with significant changes on the size of one hole pocket and the density state of the d z 2 orbital of Fe. The resonance dispersions don't always seem confined by the total gaps summed on those imperfectly nesting Fermi sheets. It is demonstrated that the c-axis dependence of both the resonance energy and its intensity in iron pnictides can be universally scaled with the distance between two adjacent Fe-As layers (d), and the k z modulation of the gap is also anticorrelated with d. These results highlight the role of interlayer coupling in iron-based superconductivity, suggesting that the interlayer pairing may also be driven by magnetic fluctuations under certain spin-orbit couplings.

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Section: Resultsmentioning

confidence: 99%

Interlayer coupling in the superconducting state of iron-based superconductors

Hong

Zhou

et al. 2023

Phys. Rev. B

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“…There are several ways to introduce dopants [15]. These are (1) hole doping is achieved with substituting A for monovalent B + (B ¼ Cs, K, Na) atoms partially in the blocking layer, and this substitution should add an excess hole into the system, for example, Ba 1−x K x Fe 2 As 2 [16,17] (2) partially substitute Fe for transition metals (Co, Ni, Pd, Rh) into FeAs layers and yields electrons into the system. In this method, dopants are directly doped into the Fe layer, which can stabilize the system; for example, Co (A(Fe 1−x Co x ) 2 As 2 ), Rh (A(Fe 2−x Rh x ) As 2 ), Ni (A(Fe 1−x Ni x ) 2 As 2 ) [18][19][20] and we get electrondoped pnictides that form an abundant phase diagram where superconductivity and magnetism exist together, and (3) replacing arsenic partially with phosphorus, and phosphorus generates a chemical pressure effect that suppress SDW and emerges superconductivity at the corresponding unit cell volume [21,22].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigation of the Interplay of Superconductivity and Magnetism in Ba1−xKxFe2As2 Superconductor in a Two-Band Model by Using the Bogoliubov Transformation Formalism

Mebratie,

Bekele

2023

Advances in Condensed Matter Physics

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The main focus of this article is to investigate the theoretical interplay of magnetism and superconductivity in a two-band model for the iron-based superconductor Ba1−xKxFe2As2. On the basis of experimental results, the two-band model Hamiltonian was considered. We obtained mathematical statements for the superconductor Ba1−xKxFe2As2 superconducting (SC) transition temperature, spin-density-wave (SDW), transition temperature, superconductivity order parameter, and SDW order parameter from the Bogoliubov transformation formalism and the model Hamiltonian. Furthermore, an expression for the dependence of the SDW transition temperature on the SDW order parameter and the dependence of the SC transition temperature on the SDW order parameter was obtained for Ba1−xKxFe2As2. By substituting the experimental and theoretical values of the parameters in the derived statements, phase diagrams of the SC transition temperature versus the SDW order parameter and the SDW transition temperature versus the SDW order parameters have been plotted to demonstrate the dependence of the SDW order parameter on transition temperatures. By combining the two-phase diagrams, we depicted the possible coexistence of superconductivity and magnetism for the Ba1−xKxFe2As2 superconductor. The phase diagrams of temperature versus SC order parameter and temperature versus SDW order parameter were also plotted to show the dependence of order parameters on temperature for the Ba1−xKxFe2As2 superconductor.

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“…Experimental evidence for magnetically driven superconductivity in these systems include: (i) reduction of the magnetic exchange energy is much larger than the superconducting condensation energy [15][16][17][18][19][20][21][22]; (ii) the observation of a spin resonance mode, which in the spin-exciton scenario indicates a sign-changing superconducting order parameter [2,[23][24][25]; and (iii) the persistence of two-dimensional (2D) high-energy AF fluctuations that resemble spin waves in magnetically ordered parent compounds [19,[26][27][28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

High-energy magnetic excitations from heavy quasiparticles in CeCu$_2$Si$_2$

Song,

Wang,

Cao

et al. 2021

Preprint

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Magnetic fluctuations is the leading candidate for pairing in cuprate, iron-based and heavy fermion superconductors. This view is challenged by the recent discovery of nodeless superconductivity in CeCu2Si2, and calls for a detailed understanding of the corresponding magnetic fluctuations. Here, we mapped out the magnetic excitations in superconducting (S-type) CeCu2Si2 using inelastic neutron scattering, finding a strongly asymmetric dispersion for E 1.5 meV, which at higher energies evolve into broad columnar magnetic excitations that extend to E 5 meV. While low-energy magnetic excitations exhibit marked three-dimensional characteristics, the high-energy magnetic excitations in CeCu2Si2 are almost two-dimensional, reminiscent of paramagnons found in cuprate and iron-based superconductors. By comparing our experimental findings with calculations in the random-phase approximation,we find that the magnetic excitations in CeCu2Si2 arise from quasiparticles associated with its heavy electron band, which are also responsible for superconductivity. Our results provide a basis for understanding magnetism and superconductivity in CeCu2Si2, and demonstrate the utility of neutron scattering in probing band renormalization in heavy fermion metals.

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Strong spin resonance mode associated with suppression of soft magnetic ordering in hole-doped Ba1-xNaxFe2As2

Cited by 9 publications

References 56 publications

Interlayer coupling in the superconducting state of iron-based superconductors

Interlayer coupling in the superconducting state of iron-based superconductors

Theoretical Investigation of the Interplay of Superconductivity and Magnetism in Ba1−xKxFe2As2 Superconductor in a Two-Band Model by Using the Bogoliubov Transformation Formalism

High-energy magnetic excitations from heavy quasiparticles in CeCu$_2$Si$_2$

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