Exciton dynamics uncovering electron fractionalization in superconducting cuprates

Abstract

Electron quasiparticles play a crucial role in simplifying the description of many-body physics in solids with surprising success. Conventional Landau's Fermi-liquid and quasiparticle theories for high-temperature superconducting cuprates have, however, received skepticism from various angles. A path-breaking framework of electron fractionalization has been established to replace the Fermi-liquid theory for systems that show the fractional quantum Hall effect and the Mott insulating phenomena; whether it captures the essential physics of the pseudogap and superconducting phases of cuprates is still an open issue. Here, we show that excitonic excitation of optimally doped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ with energy far above the superconducting-gap energy scale, about 1 eV or even higher, is unusually enhanced by the onset of superconductivity. Our finding proves the involvement of such high-energy excitons in superconductivity. Therefore, the observed enhancement in the spectral weight of excitons imposes a crucial constraint on theories for the pseudogap and superconducting mechanisms. A simple two-component fermion model which embodies electron fractionalization in the pseudogap state well explains the change, pointing toward a novel route for understanding the electronic structure of superconducting cuprates.

References in corpus (14)

• Scanning tunneling spectroscopy of high-temperature superconductors
• Electronic liquid crystal state in the high-temperature superconductor YBCO(6.45)
• Theory of universal incoherent metallic transport
• A Phenomenological Theory of The Pseudogap State
• Energy gaps in high-transition temperature cuprate superconductors
• Phase competition in trisected superconducting dome
• Evolution of electronic structure of doped Mott insulators - reconstruction of poles and zeros of Green's function
• High-energy magnetic excitations in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$: Towards a unified description of the electronic and magnetic degrees of freedom in the cuprates
• Doping evolution of the electronic structure in the single-layer cuprates Bi${}_2$Sr${}_{2-x}$La${}_x$CuO${}_{6+\delta }$: Comparison with other single-layer cuprates
• Spectroscopic Evidence for Charge Order Melting via Quantum Fluctuations in a Cuprate
• Charge Order and Superconductivity as Competing Brothers in Cuprate High-$T_{\mathrm{c}}$ Superconductors
• Doping Dependencies of Onset Temperatures for the Pseudogap and Superconductive Fluctuation in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$, Studied from both In-Plane and Out-of-Plane Magnetoresistance Measurements
• Quantum fluctuations of charge order induce phonon softening in a superconducting cuprate
• Resonant Inelastic X-Ray Scattering Spectra of Cuprate Superconductors Predicted by Model of Fractionalized Fermions

Cited by in corpus (6)

• Role of electron-phonon coupling in excitonic insulator candidate Ta2NiSe5
• Perturbative solution of fermionic sign problem in lattice Quantum Monte Carlo
• Fermi Machine -- Quantum Many-Body Solver Derived from Correspondence between Noninteracting and Strongly Correlated Fermions
• Signatures of the Fermi surface reconstruction of a doped Mott insulator in a slab geometry
• Bimagnon dispersion of La2CuO4 probed by resonant inelastic X-ray scattering
• Dominant Excitonic Superconductivity in a Three-component Hubbard Chain