Characterization of two electronic subsystems in cuprates through optical conductivity

Abstract

Understanding the physical properties of unconventional superconductors as well as of other correlated materials presents a formidable challenge. Their unusual evolution with doping, frequency, and temperature has frequently led to non-Fermi-liquid (non-FL) interpretations. Optical conductivity is a major challenge in this context. Here, the optical spectra of two archetypal cuprates, underdoped HgBa${}_2$CuO${}_{4+\delta }$ and optimally-doped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$, are interpreted based on the standard Fermi liquid (FL) paradigm. At both dopings, perfect frequency-temperature FL scaling is found to be modified by the presence of a second, gapped electronic subsystem. This non-FL component emerges as a well-defined mid-infrared spectral feature after the FL contribution -- determined independently by transport -- is subtracted. Temperature, frequency, and doping evolution of the MIR feature identify a gapped rather than dissipative response. In contrast, the dissipative response is found to be relevant for pnictides and ruthenates. Such an unbiased FL/non-FL separation is extended across the cuprate phase diagram, capturing all the key features of the normal state and providing a natural explanation why the superfluid density is attenuated on the overdoped side. Thus, we obtain a unified interpretation of optical responses and transport measurements in all analyzed physical regimes and all analyzed compounds.

19 pages, 17 figures

References in corpus (11)

• Use of X-ray scattering functions in Kramers-Kronig analysis of reflectance
• Optical determination of the relation between the electron-boson coupling function and the critical temperature in high T${}_c$ cuprates
• Electrodynamics of electron doped iron-pnictide superconductors: Normal state properties
• Non-Drude universal scaling laws for the optical response of local Fermi liquids
• Scaling of the superfluid density in high-temperature superconductors
• Demonstrating the model nature of the high-temperature superconductor HgBa${}_2$CuO${}_{4+\Delta }$
• Rise and Fall of Landau's Quasiparticles While Approaching the Mott Transition
• High-T${}_c$ cuprates: a story of two electron subsystems
• Identification of a Nematic Pair Density Wave State in Bi2Sr2CaCu2O8+x
• Electrons with Planckian scattering obey standard orbital motion in a magnetic field
• Superfluid density and two-component conductivity in hole-doped cuprates

Cited by in corpus (6)

• Investigation of Planckian behavior in a high-conductivity oxide: PdCrO${}_2$
• Transport properties and doping evolution of the Fermi surface in cuprates
• The Lorenz ratio as a guide to scattering contributions to Planckian transport
• High-entropy magnetism of murunskite
• Cuprates, Pnictides and Sulfosalts: Lessons in Functional Materials
• Hidden Universal Metal in Cuprate Superconductors