Layer thickness and substrate effects on superconductivity in epitaxial FeSe films on BLG/SiC(0001)

Fuente: arXiv
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Main Authors: Wang, Yongsong, Guo, Haojie, Etxebarria, Ane, Sajan, Sandra, Barja, Sara, Ugeda, Miguel M.
Format: Preprint
Published: 2024
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author Wang, Yongsong
Guo, Haojie
Etxebarria, Ane
Sajan, Sandra
Barja, Sara
Ugeda, Miguel M.
author_facet Wang, Yongsong
Guo, Haojie
Etxebarria, Ane
Sajan, Sandra
Barja, Sara
Ugeda, Miguel M.
contents The layered nature and simple structure of FeSe reveal this iron-based superconductor as a unique building block for the design of artificial heterostructure materials. While superconductivity develops in ultrathin films of FeSe on SrTiO3 substrates, it remains unclear whether it can be developed on more chemically inert, layered materials such as graphene. Here, we report on the characterization of the structural, chemical and electronic properties of few-layer FeSe on bilayer graphene grown on SiC(0001) using low-temperature scanning tunneling microscopy/spectroscopy (STM/STS) and X-ray photoelectron spectroscopy (XPS). STM imaging of our FeSe films with thicknesses up to three layers exhibit the tetragonal crystal structure of bulk FeSe, which is supported by XPS spectra consistent with the FeSe bulk counterpart. While our STS measurements at 340 mK reveal a metallic character for few-layer FeSe on BLG/SiC(0001), they show an absence of superconductivity, as the low-lying electronic structure exhibits a spatially anisotropic dip-like feature robust against magnetic fields. Superconductivity in FeSe/BLG/SiC(0001), however, emerges for thicker films with a transition temperature of 6 K. Our results underscore the significance of the substrate as key factor driving the suppression superconductivity in FeSe in the 2D limit.
format Preprint
id arxiv_https___arxiv_org_abs_2411_10644
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Layer thickness and substrate effects on superconductivity in epitaxial FeSe films on BLG/SiC(0001)
Wang, Yongsong
Guo, Haojie
Etxebarria, Ane
Sajan, Sandra
Barja, Sara
Ugeda, Miguel M.
Superconductivity
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
The layered nature and simple structure of FeSe reveal this iron-based superconductor as a unique building block for the design of artificial heterostructure materials. While superconductivity develops in ultrathin films of FeSe on SrTiO3 substrates, it remains unclear whether it can be developed on more chemically inert, layered materials such as graphene. Here, we report on the characterization of the structural, chemical and electronic properties of few-layer FeSe on bilayer graphene grown on SiC(0001) using low-temperature scanning tunneling microscopy/spectroscopy (STM/STS) and X-ray photoelectron spectroscopy (XPS). STM imaging of our FeSe films with thicknesses up to three layers exhibit the tetragonal crystal structure of bulk FeSe, which is supported by XPS spectra consistent with the FeSe bulk counterpart. While our STS measurements at 340 mK reveal a metallic character for few-layer FeSe on BLG/SiC(0001), they show an absence of superconductivity, as the low-lying electronic structure exhibits a spatially anisotropic dip-like feature robust against magnetic fields. Superconductivity in FeSe/BLG/SiC(0001), however, emerges for thicker films with a transition temperature of 6 K. Our results underscore the significance of the substrate as key factor driving the suppression superconductivity in FeSe in the 2D limit.
title Layer thickness and substrate effects on superconductivity in epitaxial FeSe films on BLG/SiC(0001)
topic Superconductivity
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2411.10644