Orbital superconductivity, defects and pinned nematic fluctuations in the doped iron chalcogenide FeSe${}_{0.45}$Te${}_{0.55}$

Abstract

We demonstrate that the differential conductance, $dI/dV$, measured via spectroscopic imaging scanning tunneling microscopy in the doped iron chalcogenide FeSe${}_{0.45}$Te${}_{0.55}$, possesses a series of characteristic features that allow one to extract the orbital structure of the superconducting gaps. This yields nearly isotropic superconducting gaps on the two hole-like Fermi surfaces, and a strongly anisotropic gap on the electron-like Fermi surface. Moreover, we show that the pinning of nematic fluctuations by defects can give rise to a dumbbell-like spatial structure of the induced impurity bound states, and explains the related $C_2$-symmetry in the Fourier transformed differential conductance.

5 pages + 4 figures, SI: 6 pages + 3 figures

References in corpus (5)

• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
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• Manifestations of nematic degrees of freedom in the magnetic, elastic, and superconducting properties of the iron pnictides
• Evidence for a cos(4φ) Modulation of the Superconducting Energy Gap of Optimally Doped FeTe_{0.6}Se_{0.4} Single Crystals Using Laser Angle-Resolved Photoemission Spectroscopy
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Cited by in corpus (1)

• On the Remarkable Superconductivity of FeSe and its Close Cousins