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Journal ArticleDOI

Doping-dependent Evolution of the Electronic Structure of La2-xSrxCuO4 in the Superconducting and Metallic Phases

01 Jan 2002-Physical Review B (American Physical Society)-Vol. 65, Iss: 9, pp 094504
TL;DR: The electronic structure of the LSCO system has been studied by angle-resolved photoemission spectroscopy (ARPES) as discussed by the authors, where the authors report on the evolution of the Fermi surface, the superconducting gap, and the band dispersion around the extended saddle point with hole doping in the super-conducting and metallic phases.
Abstract: The electronic structure of the ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}$ (LSCO) system has been studied by angle-resolved photoemission spectroscopy (ARPES). We report on the evolution of the Fermi surface, the superconducting gap, and the band dispersion around the extended saddle point $\mathbf{k}=(\ensuremath{\pi},0)$ with hole doping in the superconducting and metallic phases. As hole concentration x decreases, the flat band at $(\ensuremath{\pi},0)$ moves from above the Fermi level ${(E}_{\mathrm{F}})$ for $xg0.2$ to below ${E}_{\mathrm{F}}$ for $xl0.2,$ and is further lowered down to $x=0.05.$ From the leading-edge shift of ARPES spectra, the magnitude of the superconducting gap around $(\ensuremath{\pi},0)$ is found to monotonically increase as x decreases from $x=0.30$ down to $x=0.05$ even though ${T}_{c}$ decreases in the underdoped region, and the superconducting gap appears to smoothly evolve into the normal-state gap at $x=0.05.$ It is shown that the energy scales characterizing these low-energy structures have similar doping dependences. For the heavily overdoped sample $(x=0.30),$ the band dispersion and the ARPES spectral line shape are analyzed using a simple phenomenological self-energy form, and the electronic effective mass enhancement factor ${m}^{*}{/m}_{b}\ensuremath{\simeq}2$ has been found. As the hole concentration decreases, an incoherent component that cannot be described within the simple self-energy analysis grows intense in the high-energy tail of the ARPES peak. Some unusual features of the electronic structure observed for the underdoped region $(x\ensuremath{\lesssim}0.10)$ are consistent with numerical works on the stripe model.
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Journal ArticleDOI
TL;DR: A review of the most recent ARPES results on the cuprate superconductors and their insulating parent and sister compounds is presented in this article, with the purpose of providing an updated summary of the extensive literature.
Abstract: The last decade witnessed significant progress in angle-resolved photoemission spectroscopy (ARPES) and its applications. Today, ARPES experiments with 2-meV energy resolution and $0.2\ifmmode^\circ\else\textdegree\fi{}$ angular resolution are a reality even for photoemission on solids. These technological advances and the improved sample quality have enabled ARPES to emerge as a leading tool in the investigation of the high-${T}_{c}$ superconductors. This paper reviews the most recent ARPES results on the cuprate superconductors and their insulating parent and sister compounds, with the purpose of providing an updated summary of the extensive literature. The low-energy excitations are discussed with emphasis on some of the most relevant issues, such as the Fermi surface and remnant Fermi surface, the superconducting gap, the pseudogap and $d$-wave-like dispersion, evidence of electronic inhomogeneity and nanoscale phase separation, the emergence of coherent quasiparticles through the superconducting transition, and many-body effects in the one-particle spectral function due to the interaction of the charge with magnetic and/or lattice degrees of freedom. Given the dynamic nature of the field, we chose to focus mainly on reviewing the experimental data, as on the experimental side a general consensus has been reached, whereas interpretations and related theoretical models can vary significantly. The first part of the paper introduces photoemission spectroscopy in the context of strongly interacting systems, along with an update on the state-of-the-art instrumentation. The second part provides an overview of the scientific issues relevant to the investigation of the low-energy electronic structure by ARPES. The rest of the paper is devoted to the experimental results from the cuprates, and the discussion is organized along conceptual lines: normal-state electronic structure, interlayer interaction, superconducting gap, coherent superconducting peak, pseudogap, electron self-energy, and collective modes. Within each topic, ARPES data from the various copper oxides are presented.

3,077 citations


Cites background or result from "Doping-dependent Evolution of the E..."

  • ...Careful investigations by Ino et al. (2002) indicated that the Fermi surface changes from holelike to electronlike for x.0.15–0.2 as the saddle point moves from below to above EF , consistent with LDA calculations....

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  • ...Detailed angle-resolved investigations of the pseudogap in LSCO were recently reported by Ino et al. (2002) and Yoshida (2001)....

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  • ...For x,0.2 along with the opening of the pseudogap, one observes a suppression of the electronic specific heat and a decrease of the effective mass (Ino et al., 1998, 2002)....

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  • ...In contrast with the case of LSCO, where a crossover from a holelike to an electronlike Fermi surface is observed near optimal doping (Ino et al., 1999, 2002), Ding et al. (1997) suggested that a single holelike sheet of Fermi surface is characteristic of all the studied doping levels....

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Journal ArticleDOI
TL;DR: In this paper, the authors compare and contrast the advantages of two limiting perspectives on the high-temperature superconductor: weak coupling, in which correlation effects are treated as a perturbation on an underlying metallic (although renormalized) Fermi-liquid state, and strong coupling, where the magnetism is associated with well defined localized spins, and stripes are viewed as a form of micro phase separation.
Abstract: This article discusses fluctuating order in a quantum disordered phase proximate to a quantum critical point, with particular emphasis on fluctuating stripe order. Optimal strategies are derived for extracting information concerning such local order from experiments, with emphasis on neutron scattering and scanning tunneling microscopy. These ideas are tested by application to two model systems---an exactly solvable one-dimensional (1D) electron gas with an impurity, and a weakly interacting 2D electron gas. Experiments on the cuprate high-temperature superconductors which can be analyzed using these strategies are extensively reviewed. The authors adduce evidence that stripe correlations are widespread in the cuprates. They compare and contrast the advantages of two limiting perspectives on the high-temperature superconductor: weak coupling, in which correlation effects are treated as a perturbation on an underlying metallic (although renormalized) Fermi-liquid state, and strong coupling, in which the magnetism is associated with well-defined localized spins, and stripes are viewed as a form of micro phase separation. The authors present quantitative indicators that the latter view better accounts for the observed stripe phenomena in the cuprates.

1,081 citations


Cites background from "Doping-dependent Evolution of the E..."

  • ...…and La22xSrxCuO4 in some cases do exhibit features with a well-defined dispersion, and when one looks at the spectral intensity integrated over a small energy window about the Fermi energy, a Fermi surface of sorts is observed (Dessau et al., 1993; Ding et al., 1996; Ino et al., 2002)....

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  • ...However, its variation with doping is opposite to that of Qch (Ding et al., 1997; Ino et al., 2002); with increasing x , the holelike Fermi surface approaches closer to the (p,0) point, so the spanning wave vector decreases, while Qch increases....

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Journal ArticleDOI
TL;DR: Angle-resolved photoemission spectroscopy (ARPES) has emerged as a leading experimental probe for studying the complex phenomena in quantum materials, a subject of increasing importance as mentioned in this paper.
Abstract: Angle-resolved photoemission spectroscopy (ARPES) has emerged as a leading experimental probe for studying the complex phenomena in quantum materials, a subject of increasing importance The power of this technique stems from the directness and the richness of the momentum-resolved information it can provide, such as band dispersion, Fermi surface topology, and electron self-energy Over the past decade, the significantly improved energy and momentum resolution and carefully matched experiments have turned this technique into a sophisticated tool in characterizing the electronic structure of complex materials This revolution is mostly evident in the study of cuprate high-temperature superconductors More recently, this technique has played a critical role in advancing our understanding of the newly discovered iron-based superconductors and topological insulators In this paper we review some of the recent ARPES results and discuss the future perspective in this rapidly developing field

255 citations

Journal ArticleDOI
TL;DR: In this paper, the interaction between single-particle excitations and collective spin excitations in the superconducting state of high-Tc cuprates has been studied and discussed.
Abstract: We review recent experimental and theoretical results on the interaction between single-particle excitations and collective spin excitations in the superconducting state of high-Tc cuprates. We con...

249 citations

Journal ArticleDOI
TL;DR: In this article, the fundamental natures of superconductivity in strongly correlated electron systems (SCES) from a universal point of view are discussed. But, the authors focus on the superconducting properties of the SCES near the Mott transition.

229 citations