Droplet-like Fermi surfaces in the anti-ferromagnetic phase of EuFe<sub>2</sub>As<sub>2</sub>, an Fe-pnictide superconductor parent compound
de Jong, S.; van Heumen, E.; Thirupathaiah, S.; Huisman, R.; Massee, F.; Goedkoop, J. B.; Ovsyannikov, R.; Fink, J.; Dürr, H. A.; Gloskovskii, A.; Jeevan, H. S.; Gegenwart, P.; Erb, A.; Patthey, L.; Shi, M.; Follath, R.; Varykhalov, A.; Golden, M. S.; de Jong, S.; Van der Waals-Zeeman Institute, University of Amsterdam - NL-1018XE Amsterdam, The Netherlands, EU; van Heumen, E.; Van der Waals-Zeeman Institute, University of Amsterdam - NL-1018XE Amsterdam, The Netherlands, EU; Thirupathaiah, S.; Helmholtz Zentrum Berlin - Albert-Einstein-Strasse 15, 12489 Berlin, Germany, EU; Huisman, R.; Van der Waals-Zeeman Institute, University of Amsterdam - NL-1018XE Amsterdam, The Netherlands, EU; Massee, F.; Van der Waals-Zeeman Institute, University of Amsterdam - NL-1018XE Amsterdam, The Netherlands, EU; Goedkoop, J. B.; Van der Waals-Zeeman Institute, University of Amsterdam - NL-1018XE Amsterdam, The Netherlands, EU; Ovsyannikov, R.; Helmholtz Zentrum Berlin - Albert-Einstein-Strasse 15, 12489 Berlin, Germany, EU; Fink, J.; Helmholtz Zentrum Berlin - Albert-Einstein-Strasse 15, 12489 Berlin, Germany, EU; Leibniz Institute of Solid and Materials Research Dresden - P.O. Box 270116, D-01171, Dresden, Germany, EU; Dürr, H. A.; Helmholtz Zentrum Berlin - Albert-Einstein-Strasse 15, 12489 Berlin, Germany, EU; Gloskovskii, A.; Institut für Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universität 55099 Mainz, Germany, EU; Jeevan, H. S.; I. Physikalisches Institut, Georg-August-Universität - Göttingen 37077, Germany, EU; Gegenwart, P.; I. Physikalisches Institut, Georg-August-Universität - Göttingen 37077, Germany, EU; Erb, A.; Walther-Meissner-Institut - Walther-Meiß ner Strasse 8, 85748 Garching, Germany, EU; Patthey, L.; Paul Scherrer Institut, Swiss Light Source - 5232 Villigen, Switzerland; Shi, M.; Paul Scherrer Institut, Swiss Light Source - 5232 Villigen, Switzerland; Follath, R.; Helmholtz Zentrum Berlin - Albert-Einstein-Strasse 15, 12489 Berlin, Germany, EU; Varykhalov, A.; Helmholtz Zentrum Berlin - Albert-Einstein-Strasse 15, 12489 Berlin, Germany, EU; Golden, M. S.; Van der Waals-Zeeman Institute, University of Amsterdam - NL-1018XE Amsterdam, The Netherlands, EU
Журнал:
EPL (Europhysics Letters)
Дата:
2010-01-01
Аннотация:
Using angle-resolved photoemission it is shown that the low-lying electronic states of the iron pnictide parent compound EuFe<sub>2</sub>As<sub>2</sub> are strongly modified in the magnetically ordered, low-temperature, orthorhombic state compared to the tetragonal, paramagnetic case above the spin density wave transition temperature. Back-folded bands, reflected in the orthorhombic/anti-ferromagnetic Brillouin zone boundary hybridize strongly with the non-folded states, leading to the opening of energy gaps. As a direct consequence, the large Fermi surfaces of the tetragonal phase fragment, the low-temperature Fermi surface being comprised of small droplets, built up of electron- and hole-like sections. These high-resolution ARPES data are therefore in keeping with quantum oscillation and optical data from other undoped pnictide parent compounds.
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