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Title: Electron Doping of Cuprates via Interfaces with Manganites

Abstract

The electron doping of undoped high-$$T_c$$ cuprates via the transfer of charge from manganites (or other oxides) using heterostructure geometries is here theoretically discussed. This possibility is mainly addressed via a detailed analysis of photoemission and diffusion voltage experiments, which locate the Fermi level of manganites above the bottom of the upper Hubbard band of some cuprate parent compounds. A diagram with the relative location of Fermi levels and gaps for several oxides is presented. The procedure discussed here is generic, allowing for the qualitative prediction of the charge flow direction at several oxide interfaces. The addition of electrons to antiferromagnetic Cu oxides may lead to a superconducting state at the interface with minimal quenched disorder. %if the manganite used is not spin polarized. Model calculations using static and dynamical mean-field theory, supplemented by a Poisson equation formalism to address charge redistribution at the interface, support this view. The magnetic state of the manganites could be antiferromagnetic or ferromagnetic. The former is better to induce superconductivity than the latter, since the spin-polarized charge transfer will be detrimental to singlet superconductivity. It is concluded that in spite of the robust Hubbard gaps, the electron doping of undoped cuprates at interfaces appears possible, and its realization may open an exciting area of research in oxide heterostructures.

Authors:
 [1];  [1];  [1];  [1];  [1];  [2]
  1. ORNL
  2. University of Tokyo, Tokyo, Japan
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
978749
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 76; Journal Issue: 6
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CUPRATES; DIFFUSION; ELECTRONS; FERMI LEVEL; FORECASTING; MEAN-FIELD THEORY; OXIDES; PHOTOEMISSION; POISSON EQUATION; SUPERCONDUCTIVITY; correlated-electron heterostructures; high-Tc superconductivity; CMR manganites

Citation Formats

Yunoki, Seiji, Moreo, Adriana, Dagotto, Elbio R, Okamoto, Satoshi, Kancharla, Srivenkateswara S, and Fujimori, A. Electron Doping of Cuprates via Interfaces with Manganites. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.76.064532.
Yunoki, Seiji, Moreo, Adriana, Dagotto, Elbio R, Okamoto, Satoshi, Kancharla, Srivenkateswara S, & Fujimori, A. Electron Doping of Cuprates via Interfaces with Manganites. United States. doi:10.1103/PhysRevB.76.064532.
Yunoki, Seiji, Moreo, Adriana, Dagotto, Elbio R, Okamoto, Satoshi, Kancharla, Srivenkateswara S, and Fujimori, A. Mon . "Electron Doping of Cuprates via Interfaces with Manganites". United States. doi:10.1103/PhysRevB.76.064532.
@article{osti_978749,
title = {Electron Doping of Cuprates via Interfaces with Manganites},
author = {Yunoki, Seiji and Moreo, Adriana and Dagotto, Elbio R and Okamoto, Satoshi and Kancharla, Srivenkateswara S and Fujimori, A},
abstractNote = {The electron doping of undoped high-$T_c$ cuprates via the transfer of charge from manganites (or other oxides) using heterostructure geometries is here theoretically discussed. This possibility is mainly addressed via a detailed analysis of photoemission and diffusion voltage experiments, which locate the Fermi level of manganites above the bottom of the upper Hubbard band of some cuprate parent compounds. A diagram with the relative location of Fermi levels and gaps for several oxides is presented. The procedure discussed here is generic, allowing for the qualitative prediction of the charge flow direction at several oxide interfaces. The addition of electrons to antiferromagnetic Cu oxides may lead to a superconducting state at the interface with minimal quenched disorder. %if the manganite used is not spin polarized. Model calculations using static and dynamical mean-field theory, supplemented by a Poisson equation formalism to address charge redistribution at the interface, support this view. The magnetic state of the manganites could be antiferromagnetic or ferromagnetic. The former is better to induce superconductivity than the latter, since the spin-polarized charge transfer will be detrimental to singlet superconductivity. It is concluded that in spite of the robust Hubbard gaps, the electron doping of undoped cuprates at interfaces appears possible, and its realization may open an exciting area of research in oxide heterostructures.},
doi = {10.1103/PhysRevB.76.064532},
journal = {Physical Review B},
number = 6,
volume = 76,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • We have attempted electron and hole doping in Nd-based cuprates with single-layer sheets of Cu-O squares and pyramids. It was found that partial substitution of Nd/sup 3+/ sites with Ce/sup 4+/ ions introduces mobile electrons into the Nd/sub 2/CuO/sub 4/ structure which shows two-dimensional (2D) sheets of Cu-O squares with no apical oxygens. With further Sr doping into Nd/sub 2-//sub x/Ce/sub x/CuO/sub 4/, the crystalline lattice undergoes a structural transformation into the new hole-conductive compound with 2D sheets of Cu-O pyramids, which is identical with the superconducting phase discovered recently by Akimitsu et al. The hole concentration in Nd/sub 2-//submore » x//sub -//sub y/ Ce/sub x/Sr/sub y/CuO/sub 4-//sub delta/ can be increased by controlling the composition (x,y) of non-copper cations and filling oxygen vacancies (delta) as well, which give rise to superconductivity with T/sub c/ up to 30 K.« less
  • Metallic resistivity occurs at cryogenic temperatures in insulators with small carrier trap energies, e.g., superconducting cuprates. A similar metallic regime has been reported for the lanthanide (RE) manganites (RE{sup 3+}{sub 1{minus}{ital x}}A{sup 2+}{sub {ital x}})MnO{sub 3}. To interpret the anomalous resistivity {rho} as a function of temperature and magnetic field in these compounds, a model constructed from the relation for mobility activated semiconduction and the Brillouin{endash}Weiss theory of ferromagnetism has been developed. The resistivity maximum occurs at the susceptibility peak slightly above the Curie temperature {ital T}{sub {ital C}} and its magnitude is related to the hopping electron trap energymore » {ital E}{sub hop} by exp({ital E}{sub hop}/{ital kT}{sub {ital C}}). Where {ital T}{lt}{ital T}{sub {ital C}}, {rho} is metallic because {ital E}{sub hop} is small due to the collinear polarization of spins. For {ital T}{ge}{ital T}{sub {ital C}}, {ital E}{sub hop} increases to a value {approximately}0.1 eV equal to the decrease in stabilization energy of the transfer electrons caused by the transition from spin alignment to disorder. The magnetoresistance sensitivity {ital d}{rho}/{ital dH} at {ital T}={ital T}{sub {ital C}} is controlled by {ital T}{sub {ital C}} through (1/{ital T}{sub {ital C}})exp({ital E}{sub hop}/{ital kT}{sub {ital C}}). The relative sensitivity (1/{rho}){ital d}{rho}/{ital dH}, however, is proportional to 1/{ital T}{sup 2}{sub {ital C}}. These results also reinforce the concept that metallic resistivity in the superconducting cuprates occurs because of the frustration of antiferromagnetism. {copyright} {ital 1996 American Institute of Physics.}« less
  • This paper is a brief review of the status of 'phase separation' ideas in manganites and cuprates, mainly focused on the recent efforts by the authors. It is argued that in the last year considerable progress has been made in the understanding of manganites, since the famous colossal magnetoresistance peak in the resistivity versus temperature has been numerically observed in unbiased Monte Carlo simulations using realistic models (namely, including double exchange, phonons, and quenched disorder). It is also conjectured that a phenomenology similar to the one found in manganites could be present in the underdoped regime of the cuprates. Itmore » is predicted that a state with superconducting patches exists above the critical temperature in the underdoped regime, in agreement with recent scanning tunneling microscopy experiments.« less
  • This paper is a brief review of the status of phase separation ideas in manganites and cuprates, mainly focused on the recent efforts by the authors. It is argued that in the last year considerable progress has been made in the understanding of manganites, since the famous colossal magnetoresistance peak in the resistivity versus temperature has been numerically observed in unbiased Monte Carlo simulations using realistic models (namely, including double exchange, phonons, and quenched disorder). It is also conjectured that a phenomenology similar to the one found in manganites could be present in the underdoped regime of the cuprates. Itmore » is predicted that a state with superconducting patches exists above the critical temperature in the underdoped regime, in agreement with recent scanning tunneling microscopy experiments.« less