Fermi-surface topology and low-lying electronic structure of the iron-based superconductor Ca₁₀(Pt₃As₈)(Fe₂As₂)₅

Madhab Neupane, Princeton University
Chang Liu, Princeton University
Su-Yang Xu, Princeton University
Yung-Jui Wang, Northeastern University
Ni Ni, Princeton University
J. M. Allred, Princeton University
N. Alidoust, Princeton University
Hsin Lin, Northeastern University
R. S. Markiewicz, Northeastern University
A. Bansil, Northeastern University
R. J. Cava, Princeton University
M. Z. Hasan, Princeton University

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Originally published in Physical Review B v.85 (2012): 094510. DOI:

Abstract

We report a study of low-energy electronic structure and Fermi surface topology for the recently discovered iron-based superconductor Ca₁₀(Pt₃As₈)(Fe₂As₂)₅(the 10-3-8 phase, with T_c∼8 K), via angle-resolved photoemission spectroscopy (ARPES). Despite its triclinic crystal structure, ARPES results reveal a fourfold symmetric band structure with the absence of Dirac-cone-like Fermi dots (related to magnetism) found around the Brillouin zone corners in other iron-based superconductors. Considering that the triclinic lattice and structural supercell arise from the Pt₃As₈ intermediary layers, these results indicate that those layers couple only weakly to the FeAs layers in this new superconductor at least near the surface, which has implications for the determination of its pairing mechanism.