Lattice Dynamics of Ultrathin FeSe Films on SrTiO3

Abstract

Charge transfer and electron-phonon coupling (EPC) are proposed to be two important constituents associated with enhanced superconductivity in the single unit cell FeSe films on oxide surfaces. Using high-resolution electron energy loss spectroscopy combined with first-principles calculations, we have explored the lattice dynamics of ultrathin FeSe films grown on SrTiO3. We show that, despite the significant effect from the substrate on the electronic structure and superconductivity of the system, the FeSe phonons in the films are unaffected. The energy dispersion and linewidth associated with the Fe- and Se-derived vibrational modes are thickness- and temperature-independent. Theoretical calculations indicate the crucial role of antiferromagnetic correlation in FeSe to reproduce the experimental phonon dispersion. Importantly, the only detectable change due to the growth of FeSe films is the broadening of the Fuchs-Kliewer (F-K) phonons associated with the lattice vibrations of SrTiO${}_3$(001) substrate. If EPC plays any role in the enhancement of film superconductivity, it must be the interfacial coupling between the electrons in FeSe film and the F-K phonons from substrate rather than the phonons of FeSe.

arXiv comment13 gages, 8 figures

References in corpus (46)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Pseudopotentials for high-throughput DFT calculations
• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3
• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Phase Diagram and High Temperature Superconductivity at 65 K in Tuning Carrier Concentration of Single-Layer FeSe Films
• 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
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor
• Giant anharmonicity and non-linear electron-phonon coupling in MgB${}_2$; A combined first-principles calculations and neutron scattering study
• Structure determination and coexistence of superconductivity and antiferromagnetic order in (Li0.8Fe0.2)OHFeSe
• Direct observation of high temperature superconductivity in one-unit-cell FeSe films
• Evolution of high-temperature superconductivity from low-Tc phase tuned by carrier concentration in FeSe thin flakes
• Strong Interplay between Stripe Spin Fluctuations, Nematicity and Superconductivity in FeSe
• Electric-field-induced superconductivity in electrochemically-etched ultrathin FeSe films on SrTiO3 and MgO
• Critical role of substrate in the high temperature superconductivity of single layer FeSe on Nb:BaTiO${}_3$
• Magnetic ground state of FeSe
• Common Electronic Origin of Superconductivity in (Li,Fe)OHFeSe Bulk Superconductor and Single-Layer FeSe/SrTiO3 Films
• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3(110)
• Monolayer FeSe on SrTiO${}_3$
• Anomalous correlation effects and unique phase diagram of electron doped FeSe revealed by angle resolved photoemission spectroscopy
• Phonon dispersion and lifetimes in MgB2
• Enhanced superconductivity and evidence for novel pairing in single-layer FeSe on SrTiO3 thin film under large tensile strain
• Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO3 substrates
• Observation of Double-Dome Superconductivity in Potassium-Doped FeSe Thin Films
• Coexistence of isotropic s-wave and extended s-wave order parameters in FeSe as revealed by the low-temperature specific heat
• Universal Substrate Effect on the Superconductivity of FeSe Monolayer Films
• Electric field-induced superconducting transition of insulating FeSe thin film at 35 K
• High-temperature superconductivity in single-unit-cell FeSe films on anatase TiO2(001)
• The Role of SrTiO3 Phonon Penetrating into thin FeSe Films in the Enhancement of Superconductivity
• Interaction of Phonons and Dirac Fermions on the Surface of Bi2Se3: A Strong Kohn Anomaly
• Large electron-phonon interactions from FeSe phonons in a monolayer
• Interface enhanced electron-phonon coupling and high temperature superconductivity in potassium-coated ultra-thin FeSe films on SrTiO3
• Electronic Evidence of an Insulator-Superconductor Transition in Single-Layer FeSe/SrTiO3 Films
• High-temperature superconductivity in one-unit-cell FeSe films
• Observation of high-Tc superconductivity in rectangular FeSe/STO(110) monolayer
• Interface high-temperature superconductivity
• Atomically Resolved FeSe/SrTiO3(001) Interface Structure by Scanning Transmission Electron Microscopy
• Interplay between lattice and spin states degree of freedom in the FeSe superconductor: dynamic spin state instabilities
• Neutron scattering Measurements of the phonon density of states of FeSe${}_{1-x}$ superconductors
• 20 K superconductivity in heavily electron doped surface layer of FeSe bulk crystal
• The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors
• Ab initio Study of Cross-Interface Electron-Phonon Couplings in FeSe Thin Films on SrTiO${}_3$ and BaTiO${}_3$
• Density of Phonon States in Superconducting FeSe as a Function of Temperature and Pressure
• Dipolar phonons and electronic screening in monolayer FeSe on SrTiO${}_3$
• Direct imaging of electron transfer and its influence on superconducting pairing at FeSe/SrTiO3 interface

Cited by in corpus (16)

• Dynamic interfacial polaron enhanced superconductivity of FeSe/SrTiO3
• Electron phonon coupling versus photoelectron energy loss at the origin of replica bands in photoemission of FeSe on SrTiO${}_3$
• Atomic-scale observation of localized phonons at FeSe/SrTiO3 interface
• Heterostructural one-unit-cell FeSe/SrTiO3: from high-temperature superconductivity to topological states
• Interfacial Electron-Phonon Coupling Constants Extracted from Intrinsic Replica Bands in Monolayer FeSe/SrTiO${}_3$
• Unconventional pairing in single FeSe layers
• Soft phonons in the interface layer of the STO substrate can explain high temperature superconductivity in one unit cell FeSe
• Enhanced superconductivity in FeSe/SrTiO${}_3$ from the combination of forward scattering phonons and spin fluctuations
• Direct probing of a large spin-orbit coupling in the FeSe superconducting monolayer on STO: Evidence for nontrivial topological states
• Preliminary Tc calculations for iron-based superconductivity in NaFeAs, LiFeAs, FeSe and nanostructured FeSe/SrTiO3 Superconductors
• Superconductivity of the FeSe/SrTiO3 Interface in the View of BCS-BEC Crossover
• Probing lattice vibration at surface and interface of SiO${}_2$/Si with nanometer resolution
• The phonon mechanism explanation of the superconductivity dichotomy between FeSe and FeS monolayers on STO and other substrates
• Direct evidence of a charge depletion region at the interface of Van der Waals monolayers and dielectric oxides: The case of superconducting FeSe/STO
• Identifying a forward scattering superconductor through pump-probe spectroscopy
• Temperature evolution of the Fermi surface of the FeSe monolayer on SrTiO${}_3$