A universal explanation of tunneling conductance in exotic superconductors

Abstract

A longstanding mystery in understanding cuprate superconductors is the inconsistency between the experimental data measured by scanning tunneling spectroscopy (STS) and angle-resolved photoemission spectroscopy (ARPES). In particular, the gap between prominent side peaks observed in STS is much bigger than the superconducting gap observed by ARPES measurements. Here, we reconcile the two experimental techniques by generalising a theory which was previously applied to zero-dimensional mesoscopic Kondo systems to strongly correlated two-dimensional (2D) exotic superconductors. We show that the side peaks observed in tunneling conductance measurements in all these materials have a universal origin: They are formed by coherence-mediated tunneling under bias and do not directly reflect the underlying density of states (DOS) of the sample. We obtain theoretical predictions of the tunneling conductance and the density of states of the sample simultaneously and show that for cuprate and pnictide superconductors, the extracted sample DOS is consistent with the superconducting gap measured by ARPES.

Eleven pages, four figures, one table

References in corpus (5)

• Scanning tunneling spectroscopy of high-temperature superconductors
• Intra-unit-cell electronic nematicity of the high-Tc copper-oxide pseudogap states
• Unconventional Anisotropic s-Wave Superconducting Gaps of LiFeAs Iron-Pnictide Superconductor
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Cited by in corpus (2)

• The superconducting gaps in FeSe studied by soft point-contact Andreev reflection spectroscopy
• Analyzing scanning tunneling spectroscopy for Fe-based superconductor Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ and extracting $s$-wave density of states