Effect of a Zn impurity onTcand its implications for pairing symmetry in LaFeAsO1−xFx

Li, Yuke; Tao, Jun; Qian, Tao; Feng, Chunmu; Cao, Guanghan; Chen, Wei-Qiang; Zhang, Fuchun; Xu, Zhu-An

doi:10.1088/1367-2630/12/8/083008

Cited by 66 publications

(91 citation statements)

References 29 publications

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“…If there are two itinerant electrons per Fe, we find that Γ ≈ 2.2T c , which is larger than the critical value of Γ that is needed for completely suppressing T c . This is consistent with the picture that the out-of-plane Li-vacancies in LiFeAs play the same role as the nonmagnetic Zn impurities in the electron-overdoped LaFe 1−y Zn y AsO 1−x F x [32].…”

Section: Resultssupporting

confidence: 90%

“…We find that a few percent Li-deficiency can completely suppress superconductivity and change transport properties but without significant effect on the sizes of the Fermi surfaces [20] and incommensurate spin excitations [21]. By comparing our results with previous work on the SC LiFeAs [20,21], NaFe 1−x Co x As [26][27][28], BaFe 2−x T x As 2 [29][30][31], and LaFe 1−y Zn y AsO 1−x F x [32], we conclude that the stoichiometric LiFeAs is an intrinsically electronoverdoped superconductor similar to NaFe 1−x Co x with x ≈ 0.065, and that Li deficiencies affect its SC properties similar to the Zn impurity effects in the electronoverdoped iron pnictide superconductors [32]. These results naturally explain the absence of the static AF order in Li 1−x FeAs, and why superconductivity in LiFeAs is so sensitive to the Li-deficiency.…”

Section: Introductionsupporting

confidence: 58%

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Effect of Li-deficiency impurities on the electron-overdoped LiFeAs superconductor

Wang

Miao

et al. 2012

Phys. Rev. B

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We use transport, inelastic neutron scattering, and angle resolved photoemission experiments to demonstrate that the stoichiometric LiFeAs is an intrinsically electron-overdoped superconductor similar to those of the electron-overdoped NaFe1−xTxAs and BaFe2−xTxAs2 (T = Co,Ni). Furthermore, we show that although transport properties of the stoichiometric superconducting LiFeAs and Li-deficient nonsuperconducting Li1−xFeAs are different, their electronic and magnetic properties are rather similar. Therefore, the nonsuperconducting Li1−xFeAs is also in the electron overdoped regime, where small Li deficiencies near the FeAs octahedra can dramatically suppress superconductivity through the impurity scattering effect.

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Section: Resultssupporting

confidence: 90%

Section: Introductionsupporting

confidence: 58%

Effect of Li-deficiency impurities on the electron-overdoped LiFeAs superconductor

Wang

Miao

et al. 2012

Phys. Rev. B

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“…Here, the superconductivity is enhanced at low P concentrations. Although an increase of T c due to the introduction of scattering was experimentally reported in Zn-doped LaFeAs(O 1−x F x ), 25) it is not obvious whether Zn substitution introduces only impurity scattering, or whether it involves additional effects such as carrier doping and changes in the lattice parameters. More recently, electron-irradiated FeSe exhibited a slight increase of T c ≈ 0.4 K. 26) However, the effect of irradiation in FeSe with very small Fermi energies 27) is not well understood, and further investigation is needed to confirm the effect of impurity scattering.…”

mentioning

confidence: 98%

Impact of Disorder on the Superconducting Phase Diagram in BaFe₂(As₁₋_xP_x)₂

et al. 2017

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In many classes of unconventional superconductors, the question of whether the superconductivity is enhanced by the quantum-critical fluctuations on the verge of an ordered phase remains elusive. One of the most direct ways of addressing this issue is to investigate how the superconducting dome traces a shift of the ordered phase. Here, we study how the phase diagram of the iron-based superconductor BaFe 2 (As 1−x P x ) 2 changes with disorder via electron irradiation, which keeps the carrier concentrations intact. With increasing disorder, we find that the magneto-structural transition is suppressed, indicating that the critical concentration is shifted to the lower side. Although the superconducting transition temperature T c is depressed at high concentrations (x 0.28), it shows an initial increase at lower x. This implies that the superconducting dome tracks the shift of the antiferromagnetic phase, supporting the view of the crucial role played by quantum-critical fluctuations in enhancing superconductivity in this iron-based high-T c family.In strongly correlated electron systems such as heavy fermions, cuprates, and organic materials, superconductivity often emerges when the antiferromagnetic (AFM) order is suppressed through control parameters such as pressure and chemical composition. 1,2) A striking feature in these materials is that, in several cases, physical properties that deviate from the conventional Fermi-liquid theory (i.e., non-Fermi liquid properties) also appear when the AFM transition is tuned to zero temperature (T ), suggesting the existence of an AFM quantum critical point (QCP). Although it is widely believed that quantum-critical fluctuations originating from the QCP are closely related to the superconductivity through unconventional pairing mechanisms, 3,4) it remains unclear whether the QCP actually exists inside the superconducting dome. The recently discovered iron pnictides 5) also exhibit superconductivity in the vicinity of AFM order accompanying tetragonal-to-orthorhombic structural transitions. 6) These magneto-structural transitions can be suppressed by pressure or chemical substitution, 7) but the quantum criticality is often avoided by a first-order transition in several systems. 6) Among the iron pnictides, Phosphorus(P)-substituted BaFe 2 As 2 is a particularly clean system, and moreover, is unique in the fact that there is growing evidence for the existence of a QCP inside the superconducting dome near the optimal composition. 8-13) Although a QCP located at the maximum T c naturally leads to the consideration that the quantum-critical fluctuations help to enhance superconductivity, there has been no direct evidence against a scenario that it is just a coincidence. A direct test to address this issue is to investigate how the superconducting dome traces when the AFM phase is shifted. However, it has been quite challenging to perform such experiments without changing the carrier numbers or bandwidth, whose effects on the QCP and superconductivity are nontrivial. In fact, ...

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“…(28) represents the conservation of quasimomentum, and the quantity Γ αβγδ (k 1 , k 1 , k 2 , k 2 ), defined in Eq. (29), is hereinafter referred to as the rate of elastic scattering between the pair of momentum states k 1 , k 2 and k 1 , k 2 , respectively.…”

Section: Disorder Averagingmentioning

confidence: 99%

“…Studies considering SDW order coexisting with superconductivity in iron-based superconductors 28,29 found that the superconducting transition temperature can increase with increasing disorder in the underdoped regime. This is due to the fact that SDW order is affected more severely by impurity scattering than superconduc-tivity.…”

Section: Transition Temperature In the Presence Of Impurity Scattementioning

confidence: 99%

Pair breaking due to orbital magnetism in iron-based superconductors

et al. 2015

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We consider superconductivity in the presence of impurities in a two-band model suited for the description of iron-based superconductors. We analyze the effect of interband scattering processes on superconductivity, allowing for orbital, i. e., non-spin-magnetic but time-reversal-symmetry-breaking impurities. Pair-breaking in such systems is described by a nontrivial phase in an interbandscattering matrix element. We find that the transition temperature of conventional superconductors can be suppressed due to interband scattering, whereas unconventional superconductors may be unaffected. We also discuss the stability of density wave phases in the presence of impurities. As an example, we consider impurities associated with imaginary charge density waves that are of interest for iron-based superconductors.

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Effect of a Zn impurity onT_cand its implications for pairing symmetry in LaFeAsO_1−xF_x

Cited by 66 publications

References 29 publications

Effect of Li-deficiency impurities on the electron-overdoped LiFeAs superconductor

Effect of Li-deficiency impurities on the electron-overdoped LiFeAs superconductor

Impact of Disorder on the Superconducting Phase Diagram in BaFe₂(As₁₋_xP_x)₂

Pair breaking due to orbital magnetism in iron-based superconductors

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Effect of a Zn impurity onTcand its implications for pairing symmetry in LaFeAsO1−xFx

Cited by 66 publications

References 29 publications

Effect of Li-deficiency impurities on the electron-overdoped LiFeAs superconductor

Effect of Li-deficiency impurities on the electron-overdoped LiFeAs superconductor

Impact of Disorder on the Superconducting Phase Diagram in BaFe2(As1−xPx)2

Pair breaking due to orbital magnetism in iron-based superconductors

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Product

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Effect of a Zn impurity onT_cand its implications for pairing symmetry in LaFeAsO_1−xF_x

Impact of Disorder on the Superconducting Phase Diagram in BaFe₂(As₁₋_xP_x)₂