1144 Fe based superconductors: natural example of orbital selective self-doping and chemical pressure induced Lifshitz transition

Ghosh, Abyay; Sen, Smritijit; Ghosh, Haranath

doi:10.1016/j.commatsci.2020.109991

Cited by 15 publications

(11 citation statements)

References 67 publications

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“…The decrease of orbital bandwidth is considered to be corresponding to the increase of electron localization and correlation, and vice versa. 27,28 Compared with the undoped case, the hybridized band width of Fe 3d and As 4p orbitals increases under all pressures. In contrast, N(E F ) fluctuates under different pressurization.…”

Section: Resultsmentioning

confidence: 96%

The structural evolution and superconductivity under pressure for superconductor AFe₂As₂ (A = Ba, Sr)

Wang

Cai

et al. 2021

J Am Ceram Soc.

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In collinear antiferromagnetic (AFM) order, the structural evolution and electronic structure of AFe 2 As 2 (A = Ba, Sr) under hydrostatic and uniaxial pressures have been studied. The Fe-Fe distance is closely related to the AFM suppression as well as the Fe-As bond. Through analysis of Fermi surface and band diagram, the uniaxial pressure along c-axis can make the band near the Γ point to produce Lifshitz transition under the condition of lower pressure, and it is easier to suppress Fe magnetic moment. If the pressure component along c-axis is larger in the experiment, it is easier to cause the superconducting. The superconductivity of BaFe 2 As 2 and SrFe 2 As 2 under pressure may be due to the increasing of Fe 3d-and As 4p-hybridized bands width near the Fermi level.

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Section: Resultsmentioning

confidence: 96%

The structural evolution and superconductivity under pressure for superconductor AFe₂As₂ (A = Ba, Sr)

Wang

Cai

et al. 2021

J Am Ceram Soc.

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“…Because the band near Fermi level is mainly contributed by Fe 3d and As 4p orbitals, we study the hybridized bands width (HBW) of Fe 3d and As 4p orbitals near Fermi level, that is, the hybrid range of the coexistence region of Fe 3d and As 4p orbitals near Fermi level. In the study of iron-based superconductors, the decrease in orbital bandwidth is considered to be corresponding to the increase in electron localization and correlation, and vice versa [48,51]. The decrease in the bandwidth reflects the decrease in the active range of electrons, that is, the increase in localization and correlation of electrons.…”

Section: Resultsmentioning

confidence: 99%

First-principles study of the transition metal-doped iron-based superconductor AFe2As2 (A = Ba, Sr)

Wang

Liang

et al. 2021

J Mater Sci

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The characteristics of structural changes, Fe magnetic moment and electronic structure of TM (TM = Co, Ni, Rh, Pd, Ir and Pt)-doped AFe 2 As 2 (A = Ba, Sr) were studied by first-principles calculations. After the introduction of the dopants, almost all the Fe-Fe distances become longer. The nesting between the electron pockets and the hole pockets is formed. The Fermi level has a tendency to move from the hole band to the electron band. With the decrease in Fe magnetic moment, the width of Fe 3d and As 4p hybridized bands is increased, which is considered to be the decrease in electronic localized character and the increase in itinerary. The observed common features in our calculations provide information on the generation of superconductivity in iron-based superconductors AFe 2 As 2 (A = Ba, Sr).

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“…On the other hand, the c−axis component (M c ) is well preserved, leaving enough spectral weight to form the spin resonance below T c [Fig.3(a)]. The universality of c−axis preferred spin resonance supports the orbital-selective pairing in iron-pnictide superconductors[62,70,71]. The Cooper pairs might be favoured by particular orbital orders, which are robustly coupled to the local spins of Fe in most systems even at high temperatures far above T c .…”

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confidence: 92%

“…Finally, we notice that the in-plane spin excitations seem to be weakly anisotropic, such effect probably relates to the electronic nematicity involved with in-plane orbital ordering. Although the nematic order is absent in the tetragonal 1144 system, the nematic fluctuations are probed in transport measurements [15,72], and possible orbital orders are proposed in the band calculations [47,62]. Moreover, the anisotropy between M a and M b can be effectively considered as the total moment on Fe sites rotates off the diagonal direction, leading to either clockwise or counterclockwise movement of the SVCtype plaquette described by the chiral order parameter of SVDW (ϕ) [5].…”

mentioning

confidence: 99%

Preferred Spin Excitations in the Bilayer Iron-Based Superconductor CaK(Fe$_{0.96}$Ni$_{0.04}$)$_4$As$_4$ with Spin-Vortex Crystal Order

Liu,

Bourges,

Sidis

et al. 2022

Preprint

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The spin-orbit coupling (SOC) is a key to understand the magnetically driven superconductivity in iron-based superconductors, where both local and itinerant electrons are present and the orbital angular momentum is not completely quenched. Here, we report a neutron scattering study on the bilayer compound CaK(Fe0.96Ni0.04)4As4 with superconductivity coexisting with a non-collinear spin-vortex crystal magnetic order that preserves the tetragonal symmetry of Fe-Fe plane. In the superconducting state, two spin resonance modes with odd and even L symmetries due to the bilayer coupling are found similar to the undoped compound CaKFe4As4 but at lower energies. Polarization analysis reveals that the odd mode is c−axis polarized, and the low-energy spin anisotropy can persist to the paramagnetic phase at high temperature, which closely resembles other systems with in-plane collinear and c−axis biaxial magnetic orders. These results provide the missing piece of the puzzle on the SOC effect in iron-pnictide superconductors, and also establish a common picture of c−axis preferred magnetic excitations below Tc regardless of the details of magnetic pattern or lattice symmetry.

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1144 Fe based superconductors: natural example of orbital selective self-doping and chemical pressure induced Lifshitz transition

Cited by 15 publications

References 67 publications

The structural evolution and superconductivity under pressure for superconductor AFe₂As₂ (A = Ba, Sr)

The structural evolution and superconductivity under pressure for superconductor AFe₂As₂ (A = Ba, Sr)

First-principles study of the transition metal-doped iron-based superconductor AFe2As2 (A = Ba, Sr)

Preferred Spin Excitations in the Bilayer Iron-Based Superconductor CaK(Fe$_{0.96}$Ni$_{0.04}$)$_4$As$_4$ with Spin-Vortex Crystal Order

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1144 Fe based superconductors: natural example of orbital selective self-doping and chemical pressure induced Lifshitz transition

Cited by 15 publications

References 67 publications

The structural evolution and superconductivity under pressure for superconductor AFe2As2 (A = Ba, Sr)

The structural evolution and superconductivity under pressure for superconductor AFe2As2 (A = Ba, Sr)

First-principles study of the transition metal-doped iron-based superconductor AFe2As2 (A = Ba, Sr)

Preferred Spin Excitations in the Bilayer Iron-Based Superconductor CaK(Fe$_{0.96}$Ni$_{0.04}$)$_4$As$_4$ with Spin-Vortex Crystal Order

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The structural evolution and superconductivity under pressure for superconductor AFe₂As₂ (A = Ba, Sr)

The structural evolution and superconductivity under pressure for superconductor AFe₂As₂ (A = Ba, Sr)