Real-space visualization of orbital-selective superconductivity in FeSe

Fuente: arXiv
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Main Authors: Song, Sang Yong, Halász, Gábor B., Yan, Jiaqiang, Lawrie, Benjamin J., Maksymovych, Petro
Format: Preprint
Published: 2025
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author Song, Sang Yong
Halász, Gábor B.
Yan, Jiaqiang
Lawrie, Benjamin J.
Maksymovych, Petro
author_facet Song, Sang Yong
Halász, Gábor B.
Yan, Jiaqiang
Lawrie, Benjamin J.
Maksymovych, Petro
contents We investigate the orbitally resolved superconducting properties of bulk FeSe using scanning tunneling microscopy (STM). We find that the spectral weights of both the large $Δ_1$ and small $Δ_2$ superconducting gaps remain nearly unchanged at the top Se sites as the STM tip approaches atomic contact. In contrast, the spectral weight of $Δ_2$ increases significantly at the Fe and bottom Se sites. These results suggest that the gap $Δ_2$ is localized in the xy-plane and likely associated with the dxy orbital band. Furthermore, we observe a long-range suppression of the large gap $Δ_1$ near one-dimensional (1D) defects such as twin boundaries, wrinkles, and step edges, whereas $Δ_2$ remains robust. This indicates that the two superconducting gaps respond differently to such 1D defects. High-resolution measurement using a Pb-coated tip reveals localized in-gap states near 1D defects, indicating possible defect-induced magnetism. Our findings highlight the contrasting behaviors of gap $Δ_1$ and gap $Δ_2$ in response to local electronic and magnetic environments and provide real-space evidence for orbital-selective superconductivity.
format Preprint
id arxiv_https___arxiv_org_abs_2506_16384
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Real-space visualization of orbital-selective superconductivity in FeSe
Song, Sang Yong
Halász, Gábor B.
Yan, Jiaqiang
Lawrie, Benjamin J.
Maksymovych, Petro
Superconductivity
We investigate the orbitally resolved superconducting properties of bulk FeSe using scanning tunneling microscopy (STM). We find that the spectral weights of both the large $Δ_1$ and small $Δ_2$ superconducting gaps remain nearly unchanged at the top Se sites as the STM tip approaches atomic contact. In contrast, the spectral weight of $Δ_2$ increases significantly at the Fe and bottom Se sites. These results suggest that the gap $Δ_2$ is localized in the xy-plane and likely associated with the dxy orbital band. Furthermore, we observe a long-range suppression of the large gap $Δ_1$ near one-dimensional (1D) defects such as twin boundaries, wrinkles, and step edges, whereas $Δ_2$ remains robust. This indicates that the two superconducting gaps respond differently to such 1D defects. High-resolution measurement using a Pb-coated tip reveals localized in-gap states near 1D defects, indicating possible defect-induced magnetism. Our findings highlight the contrasting behaviors of gap $Δ_1$ and gap $Δ_2$ in response to local electronic and magnetic environments and provide real-space evidence for orbital-selective superconductivity.
title Real-space visualization of orbital-selective superconductivity in FeSe
topic Superconductivity
url https://arxiv.org/abs/2506.16384