The angle-resolved photoemission spectra of the superconductor (Ba1-x K x )Fe2As2 have been investigated accounting coherently for spin-orbit coupling, disorder and electron correlation effects in the valence bands combined with final state, matrix element and surface effects. Our results explain the previously obscured origins of all salient features of the ARPES response of this paradigm pnictide compound and reveal the origin of the Lifshitz transition. Comparison of calculated ARPES spectra with the underlying DMFT band structure shows an important impact of final state effects, which result for three-dimensional states in a deviation of the ARPES spectra from the true spectral function. In particular, the apparent effective mass enhancement seen in the ARPES response is not an entirely intrinsic property of the quasiparticle valence bands but may have a significant extrinsic contribution from the photoemission process and thus differ from its true value. Because this effect is more pronounced for low photoexcitation energies, soft-X-ray ARPES delivers more accurate values of the mass enhancement due to a sharp definition of the 3D electron momentum. To demonstrate this effect in addition to the theoretical study, we show here new state of the art soft-X-ray and polarisation dependent ARPES measurments.

Beijing National Laboratory for Condensed Matter Physics Beijing China

Department Chemie Physikalische Chemie Universität München Butenandtstr 5 13 81377 München Germany

Department of Applied Chemistry School of Engineering University of Tokyo 7 3 1 Hongo Bunkyo ku Tokyo 113 8656 Japan

Institute of Physics Chinese Academy of Sciences Beijing 100190 China

NewTechnologies Research Center University of West Bohemia Pilsen Czech Republic

Swiss Light Source Paul Scherrer Institute CH 5232 Villigen PSI Switzerland

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Mazin II, Johannes MD. A key role for unusual spin dynamics in ferropnictides. Nature Physics. 2009;5:141–145. doi: 10.1038/nphys1160. DOI

Mazin II, Singh DJ, Johannes MD, Du MH. Unconventional superconductivity with a sign reversal in the order parameter of lafeaso1-xfx. Phys. Rev. Lett. 2008;101 doi: 10.1103/PhysRevLett.101.057003. PubMed DOI

Mazin II, Johannes MD, Boeri L, Koepernik K, Singh DJ. Problems with reconciling density functional theory calculations with experiment in ferropnictides. Phys. Rev. B. 2008;78 doi: 10.1103/PhysRevB.78.085104. DOI

Kuroki K, Usui H, Onari S, Arita R, Aoki H. Pnictogen height as a possible switch between high-Tc nodeless and low-Tc nodal pairings in the iron-based superconductors. Phys. Rev. B. 2009;79 doi: 10.1103/PhysRevB.79.224511. DOI

Graser S, et al. Spin fluctuations and superconductivity in a three-dimensional tight-binding model for bafe2as2. Phys. Rev. B. 2010;81 doi: 10.1103/PhysRevB.81.214503. DOI

Zabolotnyy VB, et al. pi,pi) electronic order in iron arsenide superconductors. Nature. 2009;457:569–572. doi: 10.1038/nature07714. PubMed DOI

Evtushinsky DV, et al. Momentum-resolved superconducting gap in the bulk of ba1-xkxfe2as2 from combined arpes and sr measurements. New Journal of Physics. 2009;11 doi: 10.1088/1367-2630/11/5/055069. DOI

Evtushinsky DV, et al. Propeller-like low temperature fermi surface of ba1-xkxfe2as2 from magnetotransport and photoemission measurements. J. Phys. Soc. Japan. 2011;80 doi: 10.1143/JPSJ.80.023710. DOI

Evtushinsky DV, et al. Momentum dependence of the superconducting gap in ba1-xkxfe2as2. Phys. Rev. B. 2009;79 doi: 10.1103/PhysRevB.79.054517. DOI

Werner P, et al. Satellites and large doping and temperature dependence of electronic properties in hole-doped bafe2as2. Nature Physics. 2012;8:331–337. doi: 10.1038/nphys2250. DOI

Brouet V, et al. Large temperature dependence of the number of carriers in co-doped bafe2as2. Phys. Rev. Lett. 2013;110 doi: 10.1103/PhysRevLett.110.167002. PubMed DOI

Evtushinsky DV, et al. Strong electron pairing at the iron 3dxzyz orbitals in hole-doped bafe2as2 superconductors revealed by angle-resolved photoemission spectroscopy. Phys. Rev. B. 2014;89 doi: 10.1103/PhysRevB.89.064514. DOI

Brouet V, et al. Arpes view of orbitally resolved quasiparticle lifetimes in iron pnictides. Phys. Rev. B. 2016;93 doi: 10.1103/PhysRevB.93.085137. DOI

Thirupathaiah S, et al. Effect of impurity substitution on band structure and mass renormalization of the correlated fete0.5se0.5 superconductor. Phys. Rev. B. 2016;93 doi: 10.1103/PhysRevB.93.205143. DOI

Tomczak JM, van Schilfgaarde M, Kotliar G. Many-body effects in iron pnictides and chalcogenides: Nonlocal versus dynamic origin of effective masses. Phys. Rev. Lett. 2012;109 doi: 10.1103/PhysRevLett.109.237010. PubMed DOI

Backes S, Guterding D, Jeschke HO, Valent R. Electronic structure and de haas–van alphen frequencies in kfe2as2 within lda + dmft. New Journal of Physics. 2014;16 doi: 10.1088/1367-2630/16/8/083025. DOI

Berlijn T, Lin C-H, Garber W, Ku W. Do transition-metal substitutions dope carriers in iron-based superconductors? Phys. Rev. Lett. 2012;108 doi: 10.1103/PhysRevLett.108.207003. PubMed DOI

Wang L, et al. Effects of disordered ru substitution in bafe2as2: Possible realization of superdiffusion in real materials. Phys. Rev. Lett. 2013;110 doi: 10.1103/PhysRevLett.110.037001. PubMed DOI

Khan SN, Johnson DD. Lifshitz transition and chemical instabilities in bakfeas superconductors. Phys. Rev. Lett. 2014;112 doi: 10.1103/PhysRevLett.112.156401. PubMed DOI

Borisenko, S. V. et al. Direct observation of spin-orbit coupling in iron-based superconductors. Nature Physics12, 311–317, Letter (2016).

Wang X-P, et al. Orbital characters determined from fermi surface intensity patterns using angle-resolved photoemission spectroscopy. Phys. Rev. B. 2012;85 doi: 10.1103/PhysRevB.85.214518. DOI

Derondeau G, Braun J, Ebert H, Minár J. Theoretical study on the anisotropic electronic structure of antiferromagnetic bafe2as2 and co-doped ba(fe1-xcox)2as2 as seen by angle-resolved photoemission. Phys. Rev. B. 2016;93 doi: 10.1103/PhysRevB.93.144513. DOI

Yin ZP, Haule K, Kotliar G. Magnetism and charge dynamics in iron pnictides. Nature Physics. 2011;7:294–297. doi: 10.1038/nphys1923. DOI

Zhang Y-Z, Lee H, Opahle I, Jeschke HO, Valent R. Importance of itinerancy and quantum fluctuations for the magnetism in ironpnictides. J. Phys. Chem. Sol. 2011;72:324–328. doi: 10.1016/j.jpcs.2010.10.005. DOI

Ferber J, Jeschke HO, Valent R. Fermi surface topology of lafepo and lifep. Phys. Rev. Lett. 2012;109 doi: 10.1103/PhysRevLett.109.236403. PubMed DOI

Xu N, et al. Electronic band structure of baco2as2: A fully doped ferropnictide analog with reduced electronic correlations. Phys. Rev. X. 2013;3

Yin ZP, Haule K, Kotliar G. Spin dynamics and orbital-antiphase pairing symmetry in iron-based superconductors. Nature Physics. 2014;10:845–850. doi: 10.1038/nphys3116. DOI

Rotter M, et al. Spin-density-wave anomaly at 140 k in the ternary iron arsenide bafe2as2. Phys. Rev. B. 2008;78 doi: 10.1103/PhysRevB.78.020503. DOI

Rotter M, Tegel M, Johrendt D. Superconductivity at 38 k in the iron arsenide ba1-xkxfe2as2. Phys. Rev. Lett. 2008;101 doi: 10.1103/PhysRevLett.101.107006. PubMed DOI

Nakayama K, et al. Universality of superconducting gaps in overdoped ba0.3k0.7fe2as2 observed by angle-resolved photoemission spectroscopy. Phys. Rev. B. 2011;83 doi: 10.1103/PhysRevB.83.020501. DOI

Xu N, et al. Possible nodal superconducting gap and lifshitz transition in heavily hole-doped ba0.1k0.9fe2as2. Phys. Rev. B. 2013;88 doi: 10.1103/PhysRevB.88.220508. DOI

Liu C, et al. Evidence for a lifshitz transition in electron-doped iron arsenic superconductors at the onset of superconductivity. Nature Physics. 2010;6:419–423. doi: 10.1038/nphys1656. DOI

Ebert H, Ködderitzsch D, Minár J. Calculating condensed matter properties using the kkr-green’s function method – recent developments and applications. Rep. Prog. Phys. 2011;74 doi: 10.1088/0034-4885/74/9/096501. DOI

Ferber J, Foyevtsova K, Valent R, Jeschke HO. Lda + dmft study of the effects of correlation in lifeas. Phys. Rev. B. 2012;85 doi: 10.1103/PhysRevB.85.094505. DOI

Aichhorn M, et al. Dynamical mean-field theory within an augmented plane-wave framework: Assessing electronic correlations in the iron pnictide lafeaso. Phys. Rev. B. 2009;80 doi: 10.1103/PhysRevB.80.085101. DOI

Kim MG, et al. Effects of transition metal substitutions on the incommensurability and spin fluctuations in bafe2as2 by elastic and inelastic neutron scattering. Phys. Rev. Lett. 2012;109 doi: 10.1103/PhysRevLett.109.167003. PubMed DOI

Strocov VN, et al. Soft-x-ray arpes facility at the adress beamline of the sls: concepts, technical realisation and scientific applications. Synchrotron Radiat. News. 2014;21:32–44. doi: 10.1107/S1600577513019085. PubMed DOI

Strocov VN, et al. Soft-x-ray arpes at the swiss light source: From 3d materials to buried interfaces and impurities. Synchrotron Radiat. News. 2014;27:31–40. doi: 10.1080/08940886.2014.889550. DOI

Moreschini L, et al. Consequences of broken translational symmetry in fesexte1-x. Phys. Rev. Lett. 2014;112 doi: 10.1103/PhysRevLett.112.087602. DOI

Lin C-H, et al. One-fe versus two-fe brillouin zone of fe-based superconductors: Creation of the electron pockets by translational symmetry breaking. Phys. Rev. Lett. 2011;107 doi: 10.1103/PhysRevLett.107.257001. PubMed DOI

Lev LL, et al. Fermi surface of three-dimensional la1-xsrxmno3 explored by soft-x-ray arpes: Rhombohedral lattice distortion and its effect on magnetoresistance. Phys. Rev. Lett. 2015;114 doi: 10.1103/PhysRevLett.114.237601. PubMed DOI

Braun J, Donath M. Contest between surface resonances and surface states at 3d ferromagnets. Europhys. Lett. 2002;59 doi: 10.1209/epl/i2002-00145-8. DOI

Strocov VN. Intrinsic accuracy in 3-dimensional photoemission band mapping. J. Electron. Spectrosc. Relat. Phenom. 2003;130:65–78. doi: 10.1016/S0368-2048(03)00054-9. DOI

Kurtz RL, Browne DA, Mankey GJ. Final state effects in photoemission studies of fermi surfaces. J. Phys.: Cond. Mat. 2007;19

Hajiri T, et al. Three-dimensional electronic structure and interband nesting in the stoichiometric superconductor lifeas. Phys. Rev. B. 2012;85 doi: 10.1103/PhysRevB.85.094509. DOI

Ebert, H. et al. The Munich SPR-KKR package, version 6.3, http://olymp.cup.uni-muenchen.de/ak/ebert/SPRKKR. http://olymp.cup.uni-muenchen.de/ak/ebert/SPRKKR (2012).

Derondeau G, Polesya S, Mankovsky S, Ebert H, Minár J. Theoretical investigation of the electronic and magnetic properties of the orthorhombic phase of ba(fe1-xcox)2as2. Phys. Rev. B. 2014;90 doi: 10.1103/PhysRevB.90.184509. DOI

Minár J, Braun J, Ebert H. Correlation effects in magnetic materials: An ab initio investigation on electronic structure and spectroscopy. J. Electron. Spectrosc. Relat. Phenom. 2013;189 doi: 10.1016/j.elspec.2012.10.001. DOI

Braun J, et al. Exceptional behavior of d-like surface resonances on w(110): the one-step model in its density matrix formulation. New Journal of Physics. 2014;16 doi: 10.1088/1367-2630/16/1/015005. DOI

Minár J. Correlation effects in transition metals and their alloys studied using the fully self-consistent kkr-based lsda + dmft scheme. J. Phys.: Cond. Mat. 2011;23

Observation of time-reversal symmetry breaking in the band structure of altermagnetic RuO2