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Title: Pseudogap behavior in Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub 8}: Results of the generalized dynamical mean-field approach

Abstract

Pseudogap phenomena are observed for the normal underdoped phase of different high-T{sub c} cuprates. Among others, the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8-{delta}} (Bi2212) compound is one of the most studied experimentally. To describe the pseudogap regime in Bi2212, we use a novel generalized ab initio LDA + DMFT + {sigma}{sub k} hybrid scheme. This scheme is based on the strategy of one of the most powerful computational tools for real correlated materials: the local density approximation (LDA) + dynamical mean-field theory (DMFT). Conventional LDA + DMFT equations are here supplied with an additional (momentum-dependent) self-energy {sigma}{sub k} in the spirit of our recently proposed DMFT + {sigma}{sub k} approach taking into account pseudogap fluctuations. In the present model, {sigma}{sub k} describes nonlocal correlations induced by short-range collective Heisenberg-like antiferromagnetic spin fluctuations. The effective single-impurity problem of the DMFT is solved by the numerical renormalization group (NRG) method. Material-specific model parameters for the effective x{sup 2} - y{sup 2} orbital of Cu-3d shell of the Bi2212 compound, e.g., the values of intra-and interlayer hopping integrals between different Cu sites, the local Coulomb interaction U, and the pseudogap potential {delta} were obtained within the LDA and LDA + DMFT schemes. Here, wemore » report on the theoretical LDA + DMFT + {sigma}{sub k} quasiparticle band dispersion and damping, Fermi surface renormalization, momentum anisotropy of (quasi)static scattering, densities of states, spectral densities, and angular-resolved photoemission (ARPES) spectra, taking into account pseudogap and bilayer splitting effects for normal (slightly) underdoped Bi2212 ({delta} = 0.15). We show that LDA + DMFT + {sigma}{sub k} successfully describes strong (pseudogap) scattering close to Brillouin zone boundaries. Our calculated LDA + DMFT + {sigma}{sub k} Fermi surfaces and ARPES spectra in the presence of pseudogap fluctuations are almost insensitive to the bilayer splitting strength. However, our LDA-calculated value of bilayer splitting is rather small to describe the experimentally observed peak-dip-hump structure. The results obtained are in good semiquantitative agreement with various recent ARPES experiments.« less

Authors:
;  [1];  [2];  [3]
  1. Russian Academy of Sciences, Institute for Electrophysics (Russian Federation)
  2. Russian Academy of Sciences, Institute for Metal Physics (Russian Federation)
  3. Russian Academy of Sciences, Institute for Electrophysics (Russian Federation), E-mail: sadovski@iep.uran.ru
Publication Date:
OSTI Identifier:
21072474
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Experimental and Theoretical Physics; Journal Volume: 104; Journal Issue: 5; Other Information: DOI: 10.1134/S1063776107050135; Copyright (c) 2007 Nauka/Interperiodica; Article Copyright (c) 2007 Pleiades Publishing, Inc; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANISOTROPY; ANTIFERROMAGNETISM; APPROXIMATIONS; BISMUTH OXIDES; BRILLOUIN ZONES; CALCIUM OXIDES; COPPER OXIDES; CUPRATES; EMISSION SPECTRA; EQUATIONS; FERMI LEVEL; FLUCTUATIONS; HIGH-TC SUPERCONDUCTORS; MEAN-FIELD THEORY; PHOTOEMISSION; RENORMALIZATION; SCATTERING; SELF-ENERGY; SPECTRAL DENSITY; STRONTIUM OXIDES

Citation Formats

Kuchinskii, E. Z., Nekrasov, I. A., Pchelkina, Z. V., and Sadovskii, M. V.. Pseudogap behavior in Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub 8}: Results of the generalized dynamical mean-field approach. United States: N. p., 2007. Web. doi:10.1134/S1063776107050135.
Kuchinskii, E. Z., Nekrasov, I. A., Pchelkina, Z. V., & Sadovskii, M. V.. Pseudogap behavior in Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub 8}: Results of the generalized dynamical mean-field approach. United States. doi:10.1134/S1063776107050135.
Kuchinskii, E. Z., Nekrasov, I. A., Pchelkina, Z. V., and Sadovskii, M. V.. Tue . "Pseudogap behavior in Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub 8}: Results of the generalized dynamical mean-field approach". United States. doi:10.1134/S1063776107050135.
@article{osti_21072474,
title = {Pseudogap behavior in Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub 8}: Results of the generalized dynamical mean-field approach},
author = {Kuchinskii, E. Z. and Nekrasov, I. A. and Pchelkina, Z. V. and Sadovskii, M. V.},
abstractNote = {Pseudogap phenomena are observed for the normal underdoped phase of different high-T{sub c} cuprates. Among others, the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8-{delta}} (Bi2212) compound is one of the most studied experimentally. To describe the pseudogap regime in Bi2212, we use a novel generalized ab initio LDA + DMFT + {sigma}{sub k} hybrid scheme. This scheme is based on the strategy of one of the most powerful computational tools for real correlated materials: the local density approximation (LDA) + dynamical mean-field theory (DMFT). Conventional LDA + DMFT equations are here supplied with an additional (momentum-dependent) self-energy {sigma}{sub k} in the spirit of our recently proposed DMFT + {sigma}{sub k} approach taking into account pseudogap fluctuations. In the present model, {sigma}{sub k} describes nonlocal correlations induced by short-range collective Heisenberg-like antiferromagnetic spin fluctuations. The effective single-impurity problem of the DMFT is solved by the numerical renormalization group (NRG) method. Material-specific model parameters for the effective x{sup 2} - y{sup 2} orbital of Cu-3d shell of the Bi2212 compound, e.g., the values of intra-and interlayer hopping integrals between different Cu sites, the local Coulomb interaction U, and the pseudogap potential {delta} were obtained within the LDA and LDA + DMFT schemes. Here, we report on the theoretical LDA + DMFT + {sigma}{sub k} quasiparticle band dispersion and damping, Fermi surface renormalization, momentum anisotropy of (quasi)static scattering, densities of states, spectral densities, and angular-resolved photoemission (ARPES) spectra, taking into account pseudogap and bilayer splitting effects for normal (slightly) underdoped Bi2212 ({delta} = 0.15). We show that LDA + DMFT + {sigma}{sub k} successfully describes strong (pseudogap) scattering close to Brillouin zone boundaries. Our calculated LDA + DMFT + {sigma}{sub k} Fermi surfaces and ARPES spectra in the presence of pseudogap fluctuations are almost insensitive to the bilayer splitting strength. However, our LDA-calculated value of bilayer splitting is rather small to describe the experimentally observed peak-dip-hump structure. The results obtained are in good semiquantitative agreement with various recent ARPES experiments.},
doi = {10.1134/S1063776107050135},
journal = {Journal of Experimental and Theoretical Physics},
number = 5,
volume = 104,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • Using a newly devleoped EPR spin-probing methodology, we have measured magnetic penetration depth {lambda} for Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} and Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub {ital x}}. The temperature dependence of {lambda} is found to follow the relationship {lambda}={lambda}{sub 0}(1{minus}(T/T{sub {ital c}}){sup 4}){sup {minus}1/2}, with {lambda}{sub 0}=2520{plus minus}100 A and {ital T}{sub {ital c}}=119 K for Tl{sub 2}BaCa{sub 3}Cu{sub 3}O{sub 7.8+{ital x}} and {lambda}{sub 0}=2700{plus minus}100 A with {ital T}{sub {ital c}}=84 K for Bi{sub 2}Ca{sub 2}SrCu{sub 2}O{sub {ital x}}.
  • Photoelectron spectroscopy data from Bi{sub 2}Sr{sub 2}Ca{sub 1{minus}x}Y{sub x}Cu{sub 2}O{sub 8+{delta}} single crystals, for x=0, 0.16, and 0.55, are presented. It is shown that there are core level shifts related to the opening of a pseudogap and that similar shifts are observed at the opening of the superconducting gap in optimally doped samples. This result is in agreement with pair formation above T{sub C} as suggested by V.J. Emery and S.A. Kivelson [Nature (London) {bold 374}, 434 (1995)]. {copyright} {ital 1997} {ital The American Physical Society}
  • Electrical resistivity, low field diamagnetic susceptibility (constant field-cooled in various magnetic fields) and low field magnetization measurements on new high T/sub c/ superconducting copper oxides Bi/sub 2/CaSr/sub 2/Cu/sub 2/O/sub 8-{delta}/(2122)(T/sub c/=89{Kappa}) and thallium-deficient Tl/sub 0.8/Ca/sub 2/Ba/sub 2/Cu/sub 3/O/sub 8+{delta}/ (0.8,2,2,3) (T/sub c/ = 117{Kappa}) were reported. Meissner diamagnetic signal decreases with increasing magnetic field of these new superconducting copper oxides.
  • Angular magnetic field dependence of the critical currents of (Bi{sub 2} Sr{sub 2}CaCu {sub 2}O{sub 8}){sub m}/(Bi {sub 2}Sr{sub 2}CuO{sub 6}){sub n} multilayers has been investigated, {ital m} and {ital n} being the numbers of {ital c}-axis half unit cells of each phase in one layer. In the limiting case of 15 {Angstrom} thick 2212 layers and 24 {Angstrom} thick 2201 layers per multilayer unit m=1,n=2, we have achieved a superconducting system where J{sub c}(H) is independent of a magnetic field H{le}20T parallel to the layers. We demonstrate that this system behaves like an ideal 2D superconductor. {copyright} {ital 1997}more » {ital The American Physical Society}« less
  • Results of electronic structure calculations for the hole density in the two-dimensional CuO[sub 2] planes are presented in this paper for the three bismuth cuprate superconductors Bi[sub 2]Sr[sub 2]CuO[sub 6], Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8], and Bi[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10]. The hole density in these compounds arises due to electron transfer from the CuO[sub 2] planes to the Bi-O layers. Our calculations show that Bi[sub 2]Sr[sub 2]CuO[sub 6] is so highly overdoped that it is really a metal and at the limit of superconductivity. Also Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8] has a hole density which is higher thanmore » is required for a maximum value of [ital T][sub [ital c]]. On the other hand, the hole density in the three-layer compound Bi[sub 2]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10] is nearly optimum, which indicates that apart from the number of layers, an optimum value of the hole density is important for maximizing [ital T][sub [ital c]]. The hole densities in the two types of CuO[sub 2] layers in this compound are nearly equal although the central layer has a slightly lower value. As the number of CuO[sub 2] planes increases in this family of superconductors the total amount of hole carrier density per chemical formula increases due to an enhanced electron transfer to the Bi-O layers. However, this increase is small so that the hole density per CuO[sub 2] drops rapidly as the number of CuO[sub 2] planes increases.« less