Sublattice Dichotomy in Monolayer FeSe Superconductor

Abstract

The pairing mechanism behind the monolayer FeSe is one essential question for iron-based superconductors. In this work, we show the sublattice degree of freedoms of monolayer FeSe plays a special role in its pairing properties, namely the sublattice dichotomy. The high-quality monolayer FeSe samples with atomic flat $1\times 1$ topography on the SrTiO${}_3$(001) substrates are grown by molecular beam epitaxy. By comparing the tunneling spectra at $\alpha$ and $\beta$ Fe sublattices, we find the coherence peak of $\alpha$-Fe at the inner gap $+V_i$ is higher than $\beta$-Fe while the coherence peak of $\beta$-Fe at $-V_i$ is higher than $\alpha$-Fe with a similar amount. We also observed a reversed effect at the outer gap $\pm V_o$. We propose the $\eta$-pairing mechanism between $k$ and $-k+Q$ is the key mechanism for this unconventional sublattice dichotomy effect.

6 pages, 4 figures

References in corpus (10)

• High-temperature superconductivity in iron-based materials
• Scanning tunneling spectroscopy of high-temperature superconductors
• On the Remarkable Superconductivity of FeSe and its Close Cousins
• Visualizing the periodic modulation of Cooper pairing in a severely underdoped cuprate
• Revealing the Empty-State Electronic Structure of Single-Unit-Cell FeSe/SrTiO${}_3$
• Interface high-temperature superconductivity
• Incommensurate smectic phase in close proximity to the high-Tc superconductor FeSe/SrTiO3
• Atomic-scale observation of localized phonons at FeSe/SrTiO3 interface
• Observation of superconducting pair density modulation within lattice unit cell
• Paramagnetic contribution in superconductors with different-mass Cooper pairs

Cited by in corpus (2)

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