Electronic Structure and Unusual Exchange Splitting in the Spin-Density-Wave State of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>BaFe</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>Parent Compound of Iron-Based Superconductors

Yang, Liqiu; Zhang, Y; Ou, H. W.; Zhao, Jinchao; Shen, D. W.; Zhou, Bo; Jia, Wei; Chen, F; Xu, Min; He, Chi; Chen, Y; Wang, ZD; Xf, Wang; Wu, Tao; Wu, Gang; Xh, Chen; Arita, Masashi; Shimada, Kenya; Takeuchi, Masaki; Lu, ZY; Xiang, Tao; Feng, Dongxia

doi:10.1103/physrevlett.102.107002

Cited by 158 publications

(83 citation statements)

References 21 publications

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“…Below we present results for ∆ = 50 meV, which is in rough agreement with the estimates of AFM band splitting from ARPES data [33,34] and neutron scattering [35] (varying in the interval 50-100 meV), correlation length of AFM fluctuations ξ = 10a (a -lattice spacing), also in rough agrrement with netron scattering data [23,24]. In the following, all momenta are given in units of inverse lattice spacing, energies in eV.…”

supporting

confidence: 69%

“…1. Essentially this kind of electronic spectra and Fermi surfaces in new superconductors were qualitatively confirmed by angle resolved photoemission spectroscopy (ARPES), starting with the early works [14,15,16,17,18,19,20,21], followed by many further studies by the same and other authors. Most of these experiments were performed on single crystals of 122 systems, while for other compounds good quality single crystals are up to now just unavailable.…”

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confidence: 99%

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Electronic structure and possible pseudogap behavior in iron based superconductors

Kuchinskiǐ

Sadovskiǐ

2010

Jetp Lett.

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Starting from the simplified analytic model of electronic spectrum of iron -pnictogen (chalcogen) hightemperature superconductors close to the Fermi level, we discuss the influence of antiferromagneting (AFM) scattering both for stoichiometric case and the region of possible short -range order AFM fluctuations in doped compounds. Qualitative picture of the evolution of electronic spectrum and Fermi surfaces (FS) for different dopings is presented, with the aim of comparison with existing and future ARPES experiments. Both electron and hole dopings are considered and possible pseudogap behavior connected with partial FS "destruction" is demonstrated, explaining some recent experiments. PACS: 71.10. Hf, 71.18.+y, 74.25.Jb, Recent discovery of the new class of iron based hightemperature superconductors [1] stimulated intensive of experimental and theoretical efforts to understand its properties (see for the review Refs. [2,3]). Despite already the immense progress in understanding of these systems, the nature of superconducting pairing and anomalies in the normal state are still under debate.Clarification of the structure of electronic spectrum of new superconductors is crucial for explanation of their physical properties. Accordingly, since the first days, different groups have started the detailed band -structure calculations for all classes of these compounds, based primarily on different realizations of general LDA approach. These calculations were primarily performed for paramagnetic tetragonal FeAs 1111 systems [4,5,6,7], for 122 [8,9,10], for 111 [10,11,12] and α-FeSe [13], followed by many similar works by other authors. In fact, all these calculations demonstrated almost universal LDA band structure in relatively narrow energy interval (±0.1eV ) around the Fermi level, which is of relevance to superconductivity [2].In this energy interval the electronic spectrum can be modelled analytically as follows. Three "hole-like" branches of the spectrum crossing the Fermi level near the Γ point in the Brillouin zone (cf. Fig.1a) can be taken isotropic and modelled by quadratic dispersion:1) E-mail: sadovski@iep.uran.ru where m i , ε i (i = 1, 2, 3) can be easily determined from LDA calculations (e.g. for 122 system from the results of Ref.[8]). Two "electron-like" branches of the spectrum crossing the Fermi level near M(π, π) point of the reduced Brillouin zone are anisotropic and produce two elliptic isoenergetic crossections at the Fermi level (cf. Fig.1b), one of which is extened in the direction MΓ, with the second one extended in the orthogonal direction. Let us count the momentum from the M point (i.e. replace p − Q → p) and take one momentum p axis along MΓ direction and other orthogonal to it (Fig.1b). The relevant momentum projections p 1 and p 2 are connected with the usual x, y projections as. Consider one of the ellipses, e.g. those extended along the direction orthogonal to MΓ direction. Electron dispersion along MΓ can be modelled by quadratic law ε p1 (p) = p 2 2m4 − ε 4 . Dispersion along the orthog...

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confidence: 69%

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confidence: 99%

Electronic structure and possible pseudogap behavior in iron based superconductors

Kuchinskiǐ

Sadovskiǐ

2010

Jetp Lett.

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“…This is evidenced by, e.g., a relatively small value of the observed magnetic moment per Fe atom, which is around 12 − 16% of 2µ B [7,9]. In another distinction to the cuprates, electronic structure proposed by band structure calculations [15,16,17,18,19] and supported by ARPES [20,21] consists of two small hole pockets centered around Γ point (p = (0, 0)) and two small electron pockets centered around M point (p = Q = (π, π)) in the folded Brillouin zone (BZ) (two F e artoms in the unit cell, we set interatomic spacing a = 1)…”

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confidence: 98%

Magnetism, superconductivity, and pairing symmetry in iron-based superconductors

2008

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We analyze antiferromagnetism and superconductivity in novel F e−based superconductors within the itinerant model of small electron and hole pockets near (0, 0) and (π, π). We argue that the effective interactions in both channels logarithmically flow towards the same values at low energies, i.e., antiferromagnetism and superconductivity must be treated on equal footings. The magnetic instability comes first for equal sizes of the two pockets, but looses to superconductivity upon doping. The superconducting gap has no nodes, but changes sign between the two Fermi surfaces (extended s-wave symmetry). We argue that the T dependencies of the spin susceptibility and NMR relaxation rate for such state are exponential only at very low T , and can be well fitted by power-laws over a wide T range below Tc.

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“…Data around Γ, M, Z, and A were taken at 22 eV, 26 eV, 33 eV, and 17 eV respectively. All data were measured in the paramagnetic state at 150 K, 110 K, 75 K, and 40 K for P0, P15, P25 and P30 respectively to avoid the complications from the electronic structure reconstruction in the SDW and superconducting states [26,27]. …”

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confidence: 99%

Doping dependence of the electronic structure in phosphorus-doped ferropnictide superconductor BaFe2(As1−xP
Ye
¹
,
Zhang
²
,
Chen
³

et al. 2012
Phys. Rev. B
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The superconductivity in high temperature superconductors ordinarily arises when doped with hetero-valent ions that introduce charge carriers [1-4]. However, in ferropnictides, "iso-valent" doping, which is generally believed not to introduce charge carriers, can induce superconductivity as well [5][6][7][8][9][10][11]. Moreover, unlike other ferropnictides [12,13], the superconducting gap in BaFe 2 (As 1−x P x ) 2 has been found to contain nodal lines [14][15][16]. The exact nature of the "iso-valent" doping and nodal gap here are key open issues in building a comprehensive picture of the iron-based high temperature superconductors [17][18][19][20]. With angle-resolved photoemission spectroscopy (ARPES), we found that the phosphor substitution in BaFe 2 (As 1−x P x ) 2 induces sizable amount of holes into the hole Fermi surfaces, while the d xy -originated band is relatively intact. This overturns the previous common belief of "iso-valent" doping, explains why the phase diagram of BaFe 2 (As 1−x P x ) 2 is similar to those of the holedoped compounds, and rules out theories that explain the nodal gap based on vanishing d xy hole pocket.BaFe 2 (As 1−x P x ) 2 is a rather unique ferropnictide as its superconductivity is introduced by the iso-valent doping of P for As [5,6]. Unlike the hetero-valent doping that alters the carrier concentration in Ba 1−x K x Fe 2 As 2 , BaFe 2−x Co x As 2 , or LaO 1−x F x FeAs [2-4], the iso-valent doping is often considered not to alter the occupation of the Fe 3d bands, as illustrated by the density functional theory calculations of BaFe 2 As 2 and BaFe 2 P 2 as well [6,7]. Yet, surprisingly, it has a similar phase diagram just like the hetero-valent doped cases: with P doping, spin density wave (SDW) is suppressed and superconductivity (SC) emerges [6].Since P anion is smaller than As anion, and thus introduces internal strain or distortion, i.e. chemical pressure, the superconductivity introduced by iso-valent doping is associated with the unprecedented pressure dependence of the superconducting transition temperature (T c ) generally observed in ironbased superconductors [21][22][23][24]. In fact, it is the largest among all superconductors in both relative and absolute scales. For example, a T c dependency of 2-4K/GPa and sometimes even 10K/GPa is observed in BaFe 2 (As 1−x P x ) 2 , LaO 1−x F x FeAs, etc. [21,22]; and an increase of T c from 0 to above 30 K is observed in BaFe 2 As 2 and FeSe under pressure [23,24]. However, these remarkable pressure effects are still far from understood. Theoretically, P doping is predicted to alter the band structure and Fermi surface topology dramatically, considering it changes the electron hopping terms [17,25]. Particularly, it is predicted that the d z 2 -based band would go above the Fermi energy (E F ), while the d xy -based band would move down below E F with P doping. Several theories further claim that nodes will appear in the superconducting gap when the d xy hole Fermi pocket disappears [17][18][19]. Figure 1 examines the depend...

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Electronic Structure and Unusual Exchange Splitting in the Spin-Density-Wave State of theBaFe2As2Parent Compound of Iron-Based Superconductors

Cited by 158 publications

References 21 publications

Electronic structure and possible pseudogap behavior in iron based superconductors

Electronic structure and possible pseudogap behavior in iron based superconductors

Magnetism, superconductivity, and pairing symmetry in iron-based superconductors

Doping dependence of the electronic structure in phosphorus-doped ferropnictide superconductor BaFe2(As1−xP
Ye
¹
,
Zhang
²
,
Chen
³

et al. 2012
Phys. Rev. B
Self Cite
49
11
49
0
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Electronic Structure and Unusual Exchange Splitting in the Spin-Density-Wave State of theBaFe2As2Parent Compound of Iron-Based Superconductors

Cited by 158 publications

References 21 publications

Electronic structure and possible pseudogap behavior in iron based superconductors

Electronic structure and possible pseudogap behavior in iron based superconductors

Magnetism, superconductivity, and pairing symmetry in iron-based superconductors

Doping dependence of the electronic structure in phosphorus-doped ferropnictide superconductor BaFe2(As1−xPYe1, Zhang2, Chen3 et al. 2012Phys. Rev. BSelf Cite4911490View full textAdd to dashboardCite

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Doping dependence of the electronic structure in phosphorus-doped ferropnictide superconductor BaFe2(As1−xP
Ye
¹
,
Zhang
²
,
Chen
³

et al. 2012
Phys. Rev. B
Self Cite
49
11
49
0
View full text Add to dashboard Cite