Dual Enhancement of Superconductivity in FeSe/SrTiO3 via Orbital and Correlation Synergy

Abstract

In iron-based superconductors, the dz2 orbital band typically resides far below the Fermi level and has not been considered to participate in Cooper pairing. Here, using monolayer FeSe/SrTiO3 as a model system, we demonstrate that tip-induced tensile strain controllably shifts the dz2 band toward the Fermi level, driving a two-stage enhancement of superconductivity. In-plane lattice expansion first enhances electronic correlation, amplifying superconductivity in the initial stage. As strain further increases, the upward-shifted dz2 band hybridizes with the dxy band, reconstructing the pairing-active d-orbital bands and inducing a secondary, stronger gap enhancement. Collectively, these two stages enlarge the superconducting gap from 17.8 to 23.6 meV. Throughout this process, invariant Fermi wave vectors confirm that the enhancement originates from band renormalization and reconstruction rather than carrier doping. Our work establishes a route to tailor superconducting states via strain-activated electronic correlations and band engineering, and reveals a previously unrecognized orbital-selective pairing mechanism with broad implications for correlated multiband superconductors.

arXiv comment17 pages, 4 figures

References in corpus (38)

• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3
• Gap symmetry and structure of Fe-based superconductors
• Scanning tunneling spectroscopy of high-temperature superconductors
• Phase Diagram and High Temperature Superconductivity at 65 K in Tuning Carrier Concentration of Single-Layer FeSe Films
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides
• Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3
• Interface-induced superconductivity and strain-dependent spin density wave in FeSe/SrTiO3 thin films
• Heavily electron-doped electronic structure and isotropic superconducting gap in AxFe2Se2 (A=K,Cs)
• High Temperature Superconductivity in Iron Pnictides and Chalcogenides
• Effect of magnetic frustration on nematicity and superconductivity in Fe chalcogenides
• Phonon-enhanced superconductivity at the FeSe/SrTiO3 interface
• Critical role of substrate in the high temperature superconductivity of single layer FeSe on Nb:BaTiO${}_3$
• Observation of universal strong orbital-dependent correlation effects in iron chalcogenides
• Role of the orbital degree of freedom in iron-based superconductors
• Observation of Double-Dome Superconductivity in Potassium-Doped FeSe Thin Films
• Superconducting gap anisotropy in monolayer FeSe thin film
• Imaging Orbital-selective Quasiparticles in the Hund's Metal State of FeSe
• The Role of SrTiO3 Phonon Penetrating into thin FeSe Films in the Enhancement of Superconductivity
• AFM's path to atomic resolution
• Revealing the Empty-State Electronic Structure of Single-Unit-Cell FeSe/SrTiO${}_3$
• High Tc via spin fluctuations from incipient bands: application to monolayers and intercalates of FeSe
• Observation of magnetic adatom-induced Majorana vortex and its hybridization with field-induced Majorana vortex in an iron-based superconductor
• Non-Thermal Emergence of an Orbital-Selective Mott Phase in FeTe${}_{1-x}$Se${}_x$
• Correlation-Driven Electronic Reconstruction in FeTe${}_{1-x}$Se${}_x$
• Spectroscopic Evidence of Superconductivity Pairing at 83 K in Single-Layer FeSe/SrTiO3 Films
• Observation of Dirac Cone Band Dispersion in FeSe Thin Films by Photoemission Spectroscopy
• Discovery of a strain-stabilised smectic electronic order in LiFeAs
• Spatially dispersing Yu-Shiba-Rusinov states in the unconventional superconductor ${\mathrm{FeTe}}_{0.55}{\mathrm{Se}}_{0.45}$
• Incommensurate smectic phase in close proximity to the high-Tc superconductor FeSe/SrTiO3
• Nematic antiferromagnetic states in bulk FeSe
• Edge states at nematic domain walls in FeSe films
• Tunable vortex Majorana modes controlled by strain in homogeneous LiFeAs
• Basic electronic properties of iron selenide under variation of structural parameters
• Phase shift and magnetic anisotropy induced field splitting of impurity states in (Li1-xFex)OHFeSe superconductor
• Ubiquitous stripe phase and enhanced electron pairing in interfacial high-Tc superconductor FeSe/BaTiO${}_3$
• c-axis pressure induced antiferromagnetic order in optimally P-doped BaFe2(As0.70P0.30)2 superconductor
• High-Resolution Spectroscopy of the Intermediate Impurity States near a Quantum Phase Transition