Fermi surfaces and orbital polarization in superconductingCeO0.5F0.5BiS2revealed by angle-resolved photoemission spectroscopy

Abstract

We have investigated the electronic structure of BiS2-based CeO0.5F0.5BiS2 superconductor using polarization-dependent angle-resolved photoemission spectroscopy (ARPES), and succeeded in elucidating the orbital characters on the Fermi surfaces. In the rectangular Fermi pockets around X point, the straight portion parallel to the ky direction is dominated by Bi 6px character. The orbital polarization indicates the underlying quasi-one-dimensional electronic structure of the BiS2 system. Moreover, distortions on tetragonally aligned Bi could give rise to the band Jahn-Teller effect.

Localized and mixed valence state of Ce4fin superconducting and ferromagneticCeO1−xFxBiS2Sugimoto1, Ootsuki2, Paris3 et al. 2016Phys. Rev. BSelf Cite16180View full textAdd to dashboardCite

“…In a typical REO 1−x F x BiS 2 system, REO 1−x F x block layer and BiS 2 layer are alternatively stacked each other, and F substitution for O is considered as an electron dope to the electronically active BiS plane 17 whereas it has continuously been found that actual carrier concentration is always smaller than its nominal value [18][19][20] . Among the various REO 1−x F x BiS 2 compounds, CeO 1−x F x BiS 2 is very unique in that the superconductivity in the BiS 2 layer and the ferromagnetism in the CeO 1−x F x layer coexist for x > 0.4 21 .…”

Theoretical aspects of the study on the new bismuth chalcogenide based superconductors

“…7(d), the theoretical expectation seems to be different from the experiment. Also, the ARPES Fermi surfaces of NdO 0.5 F 0.5 BiS 2 (Fig.8) [47] and CeO 0.5 F 0.5 BiS 2 [48] are found to be much smaller than the theoretical expectation of 50% fluorine doped compounds. In fact, Figure 6: Comparison of the band structure and the Fermi surface calculated with (right in the lower panel) and without spin-orbit coupling [31].…”

Electronic structure predictions in Bi-O-S systems

“…Probing these symmetries experimentally could be achieved as different pairing symmetries induce qualitatively different resonance states [27]. A one-dimensional model has been considered following ARPES results pointing to the one-dimensional character of these systems [28,29] In this paper we review the experimental work and abinitio theoretical work on Bi-O-S systems, and compare the results obtained. We also go beyond the theoretical work published to bring closer together simulations and measurements and compare the obtained values of the charge carrier density.…”