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arXiv · 1504.00980

Momentum-dependent sign-inversion of orbital polarization in superconducting FeSe

Y. Suzuki·T. Shimojima·T. Sonobe·A. Nakamura·M. Sakano·H. Tsuji·J. Omachi·K. Yoshioka·M. Kuwata-Gonokami·T. Watashige·R. Kobayashi·S. Kasahara·T. Shibauchi·Y. Matsuda·Y. Yamakawa·H. Kontani·K. Ishizaka
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Abstract

We investigate the electronic reconstruction across the tetragonal-orthorhombic structural transition in FeSe by employing polarization-dependent angle-resolved photoemission spectroscopy (ARPES) on detwinned single crystals. Across the structural transition, the electronic structures around the G and M points are modified from four-fold to two-fold symmetry due to the lifting of degeneracy in dxz/dyz orbitals. The dxz band shifts upward at the G point while it moves downward at the M point, suggesting that the electronic structure of orthorhombic FeSe is characterized by a momentum-dependent sign-changing orbital polarization. The elongated directions of the elliptical Fermi surfaces (FSs) at the G and M points are rotated by 90 degrees with respect to each other, which may be related to the absence of the antiferromagnetic order in FeSe.

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Y. Suzuki, T. Shimojima, T. Sonobe, A. Nakamura, M. Sakano, H. Tsuji, J. Omachi, K. Yoshioka, M. Kuwata-Gonokami, T. Watashige, R. Kobayashi, S. Kasahara, T. Shibauchi, Y. Matsuda, Y. Yamakawa, H. Kontani, K. Ishizaka. 2015-04-04. Momentum-dependent sign-inversion of orbital polarization in superconducting FeSe. https://doi.org/10.1103/physrevb.92.205117

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