Out-of-Plane Momentum and Symmetry-Dependent Energy Gap of the Pnictide<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>Ba</mml:mi><mml:mn>0.6</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="bold">K</mml:mi><mml:mn>0.4</mml:mn></mml:msub><mml:msub><mml:mi>Fe</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>Superconductor Revealed by Angle-Resolved Photoemission Spectroscopy

Zhang, Y.; Yang, Lei; Chen, F.; Zhou, Bo; Wang, X. F.; Chen, X. H.; Arita, Masashi; Shimada, Kenya; Namatame, H.; Takeuchi, Masaki; Hu, Jiangping; Xie, B. P.; Feng, D. L.

doi:10.1103/physrevlett.105.117003

Cited by 86 publications

(66 citation statements)

References 35 publications

(23 reference statements)

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“…The development of the nodes are due to the combined effects of the increase in the hole pocket size which reduces the SC gap from intra-layer pairing and the presence of the inter-layer SC pairing. This study consistently explains the experimental observations of the c-axis gap variation in optimally hole-doped Ba 1−x K x F e 2 As 2 29,30 and the nodal behaviors in BaF e 2 As 2−x P x 28 . We also demonstrated that the inter-layer and intra-layer pairing generally competes with each other, and suggested a direct experimental test of the S ± -wave pairing symmetry through the anti-correlation of the gap modulations on the hole and electron pockets that can be measured by ARPES.…”

Section: Discussionsupporting

confidence: 87%

c-axis nodal lines induced by interlayer pairing in iron-based superconductors

Setty

Wang

et al. 2012

Phys. Rev. B

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Section: Discussionsupporting

confidence: 87%

c-axis nodal lines induced by interlayer pairing in iron-based superconductors

Setty

Wang

et al. 2012

Phys. Rev. B

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“…In the preceding section, we found that the existence of nodes in the s ± -wave pairing state of FeSCs is not required by symmetry, but may develop as a compromise [135][136][137][138][139] where ARPES measurements [140] clearly showed that the two electron pockets had nearly vanished. In addition, the superconducting transition temperature of T c = 3K was rather low compared to the moderately doped K 0.4 Ba 0.6 Fe 2 As 2 with T c = 38K [141], where all experiments indicate a nodeless superconducting gap [73,114,118,[141][142][143][144]. For this reason, there must be a nodal to nodeless transition or even a change of the pairing symmetry in between these doping regions.…”

Section: P-based Compoundsmentioning

confidence: 88%

Functional renormalization group for multi-orbital Fermi surface instabilities

Platt

Hanke

Thomale

2013

Advances in Physics

192

253

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Technological progress in material synthesis, as well as artificial realization of condensed matter scenarios via ultra-cold atomic gases in optical lattices or epitaxial growth of thin films, is opening the gate to investigate a plethora of unprecedented strongly correlated electron systems. In a large subclass thereof, a metallic state of layered electrons undergoes an ordering transition below some temperature into unconventional states of matter driven by electronic correlations, such as magnetism, superconductivity, or other Fermi surface instabilities. While this type of phenomena has been a well-established direction of research in condensed matter for decades, the variety of today's accessible scenarios pose fundamental new challenges to describe them. A core complication is the multi-orbital nature of the low-energy electronic structure of these systems, such as the multi-d orbital nature of electrons in iron pnictides and transition-metal oxides in general, but also electronic states of matter on lattices with multiple sites per unit cell such as the honeycomb or kagome lattice. In this review, we propagate the functional renormalization group (FRG) as a suited approach to investigate multi-orbital Fermi surface instabilities. The primary goal of the review is to describe the FRG in explicit detail and render it accessible to everyone both at a technical and intuitive level. Summarizing recent progress in the field of multi-orbital Fermi surface instabilities, we illustrate how the unbiased fashion by which the FRG treats all kinds of ordering tendencies guarantees an adequate description of electronic phase diagrams and often allows to obtain parameter trends of sufficient accuracy to make qualitative predictions for experiments. This review includes detailed and illustrative illustrations of magnetism and, in particular, superconductivity for the iron pnictides from the viewpoint of FRG. Furthermore, it discusses candidate scenarios for topological bulk singlet superconductivity and exotic particle-hole condensates on hexagonal lattices such as sodium-doped cobaltates, graphene doped to van Hove filling, and the kagome Hubbard model. In total, the FRG promises to be one of the most versatile and revealing numerical approaches to address unconventional Fermi surface instabilities in future fields of condensed matter research.

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“…As a comparison, Fig. 3e shows the Fermi surface cross-section of the optimally hole-doped Ba 0.6 K 0.4 Fe 2 As 2 with a T c as high as 38 K [27], where the doped potassium is outside the FeAs layer and should not induce much chemical pressure in the FeAs layer. Compared with the undoped case (Fig.…”

Section: Figmentioning

confidence: 99%

“…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]. …”

mentioning

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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Out-of-Plane Momentum and Symmetry-Dependent Energy Gap of the PnictideBa0.6K0.4Fe2As2Superconductor Revealed by Angle-Resolved Photoemission Spectroscopy

Cited by 86 publications

References 35 publications

c-axis nodal lines induced by interlayer pairing in iron-based superconductors

c-axis nodal lines induced by interlayer pairing in iron-based superconductors

Functional renormalization group for multi-orbital Fermi surface instabilities

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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Out-of-Plane Momentum and Symmetry-Dependent Energy Gap of the PnictideBa0.6K0.4Fe2As2Superconductor Revealed by Angle-Resolved Photoemission Spectroscopy

Cited by 86 publications

References 35 publications

c-axis nodal lines induced by interlayer pairing in iron-based superconductors

c-axis nodal lines induced by interlayer pairing in iron-based superconductors

Functional renormalization group for multi-orbital Fermi surface instabilities

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