Influence of the surface symmetry breaking on the magnetism, collapsing and three dimensional dispersion of Co pnictides ACo2As2 (A=Ba, Sr, Ca)

Abstract

We use angle-resolved photoemission to study the three dimensional (3D) electronic structure of Co pnictides ACo2As2 with A=Ba, Sr, Ca or a mixture of Sr and Ca. These compounds are isostructural to Fe based superconductors, but have one more electron in the Co $3d$ orbitals. Going from Ba to Ca, they become more and more 3D, eventually forming a 'collapsed' tetragonal phase, where the distance between CoAs layers is markedly reduced. The observed periodicity of the 3D electronic structure matches in each case that expected from the distance between the planes in the bulk. However, the electronic structure is better fitted by a calculation corresponding to a slab with 2 CoAs layers than to the bulk structure. We attribute this to subtle modifications of the 2D electronic structure induced by the truncation of the 3D dispersion at the surface in the ARPES measurement. We further study how this affects the electronic properties. We show that, despite this distortion, the electronic structure of CaCo2As2 is essentially that expected for a collapsed phase. Electronic correlations produce a renormalization of the electronic structure by a factor 1.4, which is not affected by the transition to the collapsed state. On the other hand, a small shift of the Fermi level reduces the density of states in the eg bands and suppresses the magnetic transition expected in CaCo2As2. Our study evidences that observing the bulk periodicity is not sufficient to ensure bulk sensitivity. It further gives direct information on the role of 3D interactions, mostly governed by Co-As hybridization, among eg and t2g orbitals. It is also useful to better understand the electronic structure of Fe superconductors and the range of validity of ARPES measurements.

References in corpus (36)

• The Puzzle of High Temperature Superconductivity in Layered Iron Pnictides and Chalcogenides
• High-temperature superconductivity in iron-based materials
• Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides
• The challenge of unravelling magnetic properties in LaFeAsO
• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Selective Mottness as a key to iron superconductors
• Superconductivity without magnetism in LiFeAs
• The Unprecedented Giant Coupling of Fe-spin State and the As-As Hybridization in Iron-Pnictide
• Hall effect and resistivity study of the magnetic transition, carrier content and Fermi liquid behavior in Ba(Fe(1-x) Cox)2As2
• On the multi-orbital band structure and itinerant magnetism of iron-based superconductors
• Renormalized behavior and proximity to a magnetic quantum critical point in BaCo${}_2$As${}_2$
• Electronic Structure of the BaFe${}_2$As${}_2$ Family of Iron Pnictides
• Nesting between hole and electron pockets in Ba(Fe1-xCox)2As2 (x=0-0.3) observed with angle-resolved photoemission
• The cleavage surface of the BaFe_(2-x)Co_(x)As_(2) and Fe_(y)Se_(1-x)Te_(x) superconductors: from diversity to simplicity
• Influence of the Third Dimension of Quasi-Two-Dimensional Cuprate Superconductors on Angle-Resolved Photoemission Spectra
• Crystallographic, Electronic, Thermal and Magnetic Properties of Single-Crystal SrCo2As2
• Orbital selective Fermi surface shifts and mechanism of high T${}_c$ superconductivity in correlated AFeAs (A=Li,Na)
• Large temperature dependence of the number of carriers in Co-doped BaFe2As2
• Spin-state transition in the Fe-pnictides
• Dynamical correlations and screened exchange on the experimental bench: spectral properties of the cobalt pnictide BaCo2As2
• Two successive field-induced spin-flop transitions in single-crystalline CaCo${}_2$As${}_2$
• Three-dimensional electronic structure of superconducting iron pnictides observed by angle-resolved photoemission spectroscopy
• Lattice collapse and the magnetic phase diagram of Sr${}_{1-x}$Ca${}_x$Co${}_2$P${}_2$
• Crystal and Magnetic Structure of CaCo{1.86}As2 Studied by X-ray and Neutron Diffraction
• Dramatic Changes in the Electronic Structure Upon Transition to the Collapsed Tetragonal Phase in CaFe2As2
• Physical Properties of Metallic Antiferromagnetic CaCo{1.86}As2 Single Crystals
• Electronic band structure of BaCo${}_2$As${}_2$: a fully-doped ferropnictide with reduced electronic correlations
• Correlation effects in the tetragonal and collapsed tetragonal phase of CaFe2As2
• Metamagnetic transition in Ca${}_{1-x}$Sr${}_x$Co${}_2$As${}_2$($x$ = 0 and 0.1) single crystals
• Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe${}_2$As${}_2$
• Crystallography and Physical Properties of BaCo2As2, Ba{0.94}K{0.06}Co2As2 and Ba{0.78}K{0.22}Co2As2
• Structural origin of the anomalous temperature dependence of the local magnetic moments in the CaFe${}_2$As${}_2$ family of materials
• Angle-Resolved Photoemission Spectroscopy Study of BaCo2As2
• Tetragonal and collapsed-tetragonal phases of CaFe2As2 -- a view from angle-resolved photoemission and dynamical mean field theory
• ARPES view of orbitally resolved quasiparticle lifetimes in iron pnictides
• Drastic electronic structure reconstruction of Ca${}_{1-x}$Pr${}_x$Fe${}_2$As${}_2$ in the collapsed tetragonal phase

Cited by in corpus (3)

• Frustrated magnetism in tetragonal CoSe, analogue to superconducting FeSe
• Is BaCr${}_2$As${}_2$ symmetrical to BaFe${}_2$As${}_2$ with respect to half $3d$ shell filling?
• Novel approaches to spectral properties of correlated electron materials: From generalized Kohn-Sham theory to screened exchange dynamical mean field theory