Dramatic Changes in the Electronic Structure Upon Transition to the Collapsed Tetragonal Phase in CaFe2As2

Abstract

We use angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations to study the electronic structure of CaFe${}_2$As${}_2$ in previously unexplored collapsed tetragonal (CT) phase. This unusual phase of the iron arsenic high temperature superconductors was hard to measure as it exists only under pressure. By inducing internal strain, via the post growth, thermal treatment of the single crystals, we were able to stabilize the CT phase at ambient-pressure. We find significant differences in the Fermi surface topology and band dispersion data from the more common orthorhombic-antiferromagnetic or tetragonal-paramagnetic phases, consistent with electronic structure calculations. The top of the hole bands sinks below the Fermi level, which destroys the nesting present in parent phases. The absence of nesting in this phase along with apparent loss of Fe magnetic moment, are now clearly experimentally correlated with the lack of superconductivity in this phase.

5 pages, 4 figures, accepted in PRB(RC)

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Cited by in corpus (37)

• Role of the orbital degree of freedom in iron-based superconductors
• Effects of strain on the electronic structure, superconductivity, and nematicity in FeSe studied by angle-resolved photoemission spectroscopy
• Unfolding of the electronic structure through the induced representations of space groups: Application to Fe-based superconductors
• Pressure induced half-collapsed-tetragonal phase in CaKFe${}_4$As${}_4$
• Correlation effects in the tetragonal and collapsed tetragonal phase of CaFe2As2
• Hydrostatic and uniaxial pressure tuning of iron-based superconductors: Insights into superconductivity, magnetism, nematicity and collapsed tetragonal transitions
• Fermi-Surface Reconstruction and Complex Phase Equilibria in CaFe${}_2$As${}_2$
• Preserved entropy and fragile magnetism
• The suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by 75As NMR-NQR measurements
• Structural origin of the anomalous temperature dependence of the local magnetic moments in the CaFe${}_2$As${}_2$ family of materials
• Origin of the superconducting state in the collapsed tetragonal phase of KFe2As2
• Trends in pressure-induced layer-selective half-collapsed tetragonal phases in the iron-based superconductor family $AeA$Fe${}_4$As${}_4$
• Optical properties of $A$Fe${}_2$As${}_2$ ($A=$Ca, Sr, and Ba) single crystals
• Tetragonal and collapsed-tetragonal phases of CaFe2As2 -- a view from angle-resolved photoemission and dynamical mean field theory
• Superconductivity in Uncollapsed Tetragonal LaFe2As2
• Volovik Effect and Fermi-Liquid Behavior in the s-Wave Superconductor CaPd2As2: 75As NMR-NQR Measurements
• Wavefunctions, electronic localization and bonding properties for correlated materials beyond the Kohn-Sham formalism
• Ab-initio perspective on structural and electronic properties of iron-based superconductors
• Transition to collapsed tetragonal phase in CaFe2As2 single crystals as seen by 57Fe Mossbauer spectroscopy
• Emergent electronic structure of CaFe2As2
• Collapsed Tetragonal Phase Transition in LaRu${}_2$P${}_2$
• Universal enhancement of superconductivity in two dimensional semiconductors at low doping by electron-electron interaction
• Antiferromagnetic spin correlations and pseudogap-like behavior in Ca(Fe1-xCox)2As2 studied by 75As nuclear magnetic resonance and anisotropic resistivity
• Fermi-surface topological phase transition and horizontal order-parameter nodes in CaFe${}_2$As${}_2$ under pressure
• Dimensionality, nematicity and Superconductivity in Fe-based systems
• Combined effects of transition metal (Ni and Rh) substitution and annealing/quenching on physical properties of CaFe${}_2$As${}_2$
• Sign change in c-axis thermal expansion and lattice collapse by Ni substitution in Co1-xNixZr2 superconductors
• Hidden robust presence of a hole Fermi surface in a heavily electron doped iron based superconductor LaFe${}_2$As${}_2$
• Lifshitz Transitions in 122-Pnictides Under Pressure
• Role of electron-electron interactions in the charge dynamics of rare-earth-doped CaFe2As2
• Reversible Tuning of the Collapsed Tetragonal Phase Transition in CaFe2As2 by Separate Control of Chemical Pressure and Electron Doping
• Influence of the surface symmetry breaking on the magnetism, collapsing and three dimensional dispersion of Co pnictides ACo2As2 (A=Ba, Sr, Ca)
• Drastic electronic structure reconstruction of Ca${}_{1-x}$Pr${}_x$Fe${}_2$As${}_2$ in the collapsed tetragonal phase
• Optical spectroscopy study of the collapsed tetragonal phase of CaFe${}_2$(As${}_{0.935}$P${}_{0.065}$)${}_2$ single crystals
• Carrier Tuning of Stoner Ferromagnetism in ThCr${}_2$Si${}_2$-Structure Cobalt Arsenides
• Superconducting properties and electronic structure of CuAl2-type transition-metal zirconide Fe1-xNixZr2
• Observation of the Dirac Dispersions in Co-doped CaFe2As2