Strong energy-momentum dispersion of phonon-dressed carriers in the lightly doped band insulator SrTiO${}_3$

Abstract

Much progress has been made recently in the study of the effects of electron-phonon (el-ph) coupling in doped insulators using angle resolved photoemission (ARPES), yielding evidence for the dominant role of el-ph interactions in underdoped cuprates. As these studies have been limited to doped Mott insulators, the important question arises how this compares with doped band insulators where similar el-ph couplings should be at work. The archetypical case is the perovskite SrTiO${}_3$ (STO), well known for its giant dielectric constant of 10000 at low temperature, exceeding that of La${}_2$CuO${}_4$ by a factor of 500. Based on this fact, it has been suggested that doped STO should be the archetypical bipolaron superconductor. Here we report an ARPES study from high-quality surfaces of lightly doped SrTiO${}_3$. Comparing to lightly doped Mott insulators, we find the signatures of only moderate electron-phonon coupling: a dispersion anomaly associated with the low frequency optical phonon with a ${\lambda }^{\prime }\sim 0.3$ and an overall bandwidth renormalization suggesting an overall ${\lambda }^{\prime }\sim 0.7$ coming from the higher frequency phonons. Further, we find no clear signatures of the large pseudogap or small polaron phenomena. These findings demonstrate that a large dielectric constant itself is not a good indicator of el-ph coupling and highlight the unusually strong effects of the el-ph coupling in doped Mott insulators.

References in corpus (6)

• Quantum oscillations and the Fermi surface in an underdoped high-Tc superconductor
• Electron-phonon interaction and charge carrier mass enhancement in SrTiO3
• Polaronic behavior of undoped high-Tc cuprates
• Doping dependence of the coupling of electrons to bosonic modes in the single-layer high-temperature Bi2Sr2CuO6 superconductor
• Origin of the large phonon band-gap in SrTiO3 and the vibrational signatures of ferroelectricity in ATiO3 perovskite: First principles lattice dynamics and inelastic neutron scattering of PbTiO3, BaTiO3 and SrTiO3
• Coherent and Incoherent States of Electron-doped SrTiO3

Cited by in corpus (35)

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• Quasiparticle dynamics and spin-orbital texture of the SrTiO3 two-dimensional electron gas
• Theory of the SrTiO3 Surface State Two-Dimensional Electron Gas
• Superconductivity at very low density: the case of strontium titanate
• Mixed Dimensionality of Confined Conducting Electrons in the Surface Region of SrTiO${}_3$
• Ubiquitous strong electron phonon coupling at the interface of FeSe/SrTiO3
• Anomalously large capacitance of a plane capacitor with a two-dimensional electron gas
• A possible mechanism for superconductivity in doped SrTiO3
• Shubnikov-de Haas effect in low electron density SrTiO3: Conduction band edge of SrTiO3 redux
• Fermi surface and superconductivity in low-density high-mobility δ-doped SrTiO3
• d0 Perovskite-Semiconductor Electronic Structure
• Isotope tuning of the superconducting dome of strontium titanate
• Polaronic metal in lightly doped high-Tc cuprates
• Quantum ferroelectric instabilities in superconducting SrTiO${}_3$
• High Temperature Superconductivity: the explanation
• Stripe charge ordering in SrO-terminated SrTiO3(001) surfaces
• Orientation-dependent electron-phonon coupling in interfacial superconductors LaAlO3/KTaO3
• Large polarons as key quasiparticles in SrTiO3 and SrTiO3-based heterostructures
• Key pairing interaction in layered doped ionic insulators
• High-density two-dimensional electron system induced by oxygen vacancies in ZnO
• Facile ab initio approach for self-localized polarons from canonical transformations
• Formation and observation of a quasi-two-dimensional $d_{xy}$ electron liquid in epitaxially stabilized Sr${}_{2-x}$La${}_x$TiO${}_4$ thin films
• 2D surprises at the surface of 3D materials: confined electron systems in transition metal oxides
• Diamagnetism of real-space pairs above Tc in hole doped cuprates
• Strong interplay between electron-phonon interaction and disorder in low doped systems
• Spectroscopic signatures of nonpolarons : the case of diamond
• All-coupling polaron optical response: analytic approaches beyond the adiabatic approximation
• Energy versus wave vector for the conduction band of La-doped SrTiO_3 interpreted by mixed-polaron theory
• Ground state features and spectral properties of large polaron liquids from low to high charge densities
• Direct observation of two-dimensional small polarons at correlated oxide interface
• Strong-coupling superconductivity beyond BCS and the key pairing interaction in cuprate superconductors
• Orbital-resolved anisotropic electron pockets in electron-doped SrTiO3 observed by ARPES
• Contribution of interband effects caused by long-wavelength transverse optical phonons to electron-phonon coupling in doped polar insulators