Electronic structure of (Ca0.85La0.15)FeAs2

Liu, Z.-H.; Kim, T. K.; Sala, Alberto; Shimoyama, Jun–ichi; Büchner, B.; Борисенко, С. В.

doi:10.1063/1.4907876

Cited by 14 publications

(17 citation statements)

References 32 publications

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“…Thus, whether this prediction as well applies to the corresponding electron-doped superconductor Ca 1−x La x FeAs 2 with a T c as high as 40 K would be an ideal touchstone for this intriguing model. Besides, so far there still have been no specific reports on this characteristic but tenuous feature in the band dispersion measurements of 112-type iron-based superconductors [25][26][27] .…”

Section: Pacs Numbersmentioning

confidence: 99%

Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca0.9La0.1FeAs2

Liu

Xing

et al. 2016

Applied Physics Letters

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CaFeAs 2 is a parent compound of recently discovered 112-type iron-based superconductors. It is predicted to be a staggered intercalation compound that naturally integrates both quantum spin Hall insulating and superconducting layers and an ideal system for the realization of Majorana modes. We performed a systematical angle-resolved photoemission spectroscopy and first-principle calculation study of the slightly electron-doped CaFeAs 2 . We found that the zigzag As chain of 112-type iron-based superconductors play a considerable role in the low-energy electronic structure, resulting in the characteristic Dirac-cone like band dispersion as the prediction. Our experimental results further confirm that these Dirac cones only exists around the X but not Y points in the Brillouin zone, breaking the S 4 symmetry at iron sites. Our findings present the compelling support to the theoretical prediction that the 112-type iron-based superconductors might host the topological nontrivial edge states. The slightly electron doped CaFeAs 2 would provide us a unique opportunity to realize and explore Majorana fermion physics.

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Section: Pacs Numbersmentioning

confidence: 99%

Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca0.9La0.1FeAs2

Liu

Xing

et al. 2016

Applied Physics Letters

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“…ARPES measurements on

{Ca}_{1 - x} {La}_{x} {FeAs}_{2}

indicated a band structure similar to the other

normalpnictide

systems consisting of three hole like bands (

d_{xz}, d_{yz}, d_{xy}

character) at the

Γ

point and two electron like bands (

d_{xz}, d_{xy}

types) at the M point of the BZ , with reasonable nesting mostly originating from the Fe’

3 d

electrons (see Fig. ).…”

Section: Electronic Structurementioning

confidence: 60%

“…Band structure of

{Ca}_{1 - x} {La}_{x} {FeAs}_{2}

projected to the in‐plane BZ as obtained from ARPES measurements (). (Reprinted with permission from Liu

italicet italical .

Section: Electronic Structurementioning

confidence: 99%

“…In the past two years, research interest again increased for

{Ca}_{1 - x} {La}_{x} {FeAs}_{2}

due to the availability of single crystals, high’

T_{c}

in the bulk phase, and the possibility of a range of substitutions. Significant amount of research work was done earlier in other 112‐type materials like LaPd x Sb 2 (), LaPd x Bi 2 , CeNi x Sb 2 , LaNi x Sb 2 , etc.…”

Section: Introductionmentioning

confidence: 99%

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Superconductivity and Dirac fermions in 112‐phase pnictides

Ray

Alff

2016

Physica Status Solidi (b)

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This article reviews the current research on the 112‐phase of pnictides. The 112‐phase has gained augmented attention due to the recent discovery of high‐temperature superconductivity in Ca1−xLaxFeAs2 with a maximum critical temperature Tnormalc∼ 47thinmathspacenormalK upon Sb substitution. The structural, magnetic, and electronic properties of Ca1−xLaxFeAs2 bear some similarities with other superconducting pnictide phases, however, the different valence states of the pnictogen and the presence of a metallic spacer layer are unique features of the 112‐system. Low‐temperature superconductivity which coexists with antiferromagnetic order was observed in transition metal (Ni, Pd) deficient 112‐compounds like CeNixBi2, LaPdxBi2, LaPdxSb2, LaNixSb2. Besides superconductivity, the presence of naturally occurring anisotropic Dirac Fermionic states were observed in the layered 112‐compounds SrMnBi2, CaMnBi2, LaAgBi2 which are of significant interest for future nanoelectronics as an alternative to graphene. In these compounds, the linear energy dispersion resulted in a high magnetoresistance that stayed unsaturated even at the highest applied magnetic fields. Here, we describe various 112‐type materials systems combining experimental results and theoretical predictions to stimulate further research on this less well‐known member of the pnictide family.

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“…Figures 2(c) and 2(d) show the intensity plots of band dispersion along ZA in p and r geometries, respectively.The data taken with different geometries allow us to detect the orbital character of the bands. According to the symmetry analysis and by analogy with others IBS,[12][13][14][15][27][28][29][30][31] we identify the orbital character of each band. At the Z point,FIG.…”

mentioning

confidence: 99%

Reduced electronic correlation effects in half substituted Ba(Fe1−xCox)2As2

Liu

Yaresko

et al. 2018

Applied Physics Letters

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We report a comprehensive study of the tridimensional nature and orbital character of the lowenergy electronic structure in 50% Cobalt doped Ba(Fe 1Àx Co x) 2 As 2 (d 6.5), by using polarizationand photon energy-dependent angle-resolved photoemission spectroscopy. An extra electron-like Fermi surface is observed around the Brillouin zone boundary compared with isoelectronic K y Fe 2Àx Se 2 (d 6.5). The bands near the Fermi level (E F) are mainly derived from Fe/Co 3d t 2g orbitals, revealing visible dispersions along the k z direction. In combination with the local density approximation and the dynamical mean-field theory calculations, we find that the As 4p bands are non-renormalized and the whole 3d band needs to be renormalized by a "single" factor of $1.6, indicating moderate electronic correlation effects. The "single" factor description of the correlation strength among the different 3d orbitals is also in sharp contrast to orbital-dependent correlation effects in BaFe 2 As 2. Our findings indicate a remarkable reduction of correlation effects with little difference among 3d orbitals in BaFeCoAs 2 , due to the increased filling of the electronic 3d shell in the presence of significant Hund's coupling. The results support that the electronic correlation effects and multiple orbital physics play an important role in the superconductivity of the 122 system and in other ferropnictides.

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Electronic structure of (Ca0.85La0.15)FeAs2

Cited by 14 publications

References 32 publications

Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca0.9La0.1FeAs2

Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca0.9La0.1FeAs2

Superconductivity and Dirac fermions in 112‐phase pnictides

Reduced electronic correlation effects in half substituted Ba(Fe1−xCox)2As2

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