High-density two-dimensional small polaron gas in a delta-doped Mott insulator

Abstract

Heterointerfaces in complex oxide systems open new arenas in which to test models of strongly correlated material, explore the role of dimensionality in metal-insulator-transitions (MITs) and small polaron formation. Close to the quantum critical point Mott MITs depend on band filling controlled by random disordered substitutional doping. Delta-doped Mott insulators are potentially free of random disorder and introduce a new arena in which to explore the effect of electron correlations and dimensionality. Epitaxial films of the prototypical Mott insulator GdTiO3 are delta-doped by substituting a single (GdO)+1 plane with a monolayer of charge neutral SrO to produce a two-dimensional system with high planar doping density. Unlike metallic SrTiO3 quantum wells in GdTiO3 the single SrO delta-doped layer exhibits thermally activated DC and optical conductivity that agree in a quantitative manner with predictions of small polaron transport but with an extremely high two-dimensional density of polarons, ~ 7E14 cm-2

References in corpus (12)

• Kramers-Kronig constrained variational analysis of optical spectra
• Hall-Effect Sign Anomaly and Small-Polaronic Conduction in (La_{1-x}Gd_x)_{0.67}Ca_{0.33}MnO_3
• Electrostatic carrier doping of GdTiO3/SrTiO3 interfaces
• Electron-phonon interaction and charge carrier mass enhancement in SrTiO3
• Nonlinear Hall effect and multichannel conduction in LaTiO3/SrTiO3 superlattices
• Many-body large polaron optical conductivity in SrTi${}_{1-x}$Nb${}_x$O${}_3$
• Optical Study of the Free Carrier Response of LaTiO3/SrTiO3 Superlattices
• Toward an artificial Mott insulator: Correlations in confined, high-density electron liquids in SrTiO3
• Mott-Hubbard exciton in the optical conductivity of YTiO3 and SmTiO3
• Dimer Mott Insulator in an Oxide Heterostructure
• Modulation doping to control the high-density electron gas at a polar/non-polar oxide interface
• Heavy-Fermion Formation at the Metal-to-Insulator Transition in Gd${}_{1-x}$Sr${}_x$TiO${}_3$

Cited by in corpus (7)

• Real-time decay of a highly excited charge carrier in the one-dimensional Holstein model
• Energetic, spatial and momentum character of a buried interface: the two-dimensional electron gas between two metal oxides
• Correlation between metal-insulator transitions and structural distortions in high-electron-density SrTiO3 quantum wells
• Towards Mott design by $\delta$-doping of strongly correlated titanates
• Observation by resonant angle-resolved photoemission of a critical thickness for 2-dimensional electron gas formation in SrTiO${}_3$ embedded in GdTiO${}_3$
• Determining a hopping polarons bandwidth from its Seebeck coefficient: Measuring the disorder energy of a non-crystalline semiconductor
• Polaron transport of amorphous semiconductors with embedded crystallites