NOVEL MANY-BODY EFFECTS IN PHOTOEMISSION AND INVERSE PHOTOEMISSION SPECTRA OF ULTRATHIN TRANSITION-METAL FILMS

1991 ◽  
Vol 05 (08) ◽  
pp. 1147-1178 ◽  
Author(s):  
CHANGFENG CHEN
Keyword(s):  
Transition Metal ◽  
Local Density ◽  
Many Body ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Nickel Iron ◽  
Correlated Electron ◽  
Inverse Photoemission ◽  
Recent Developments ◽  
Many Body Effects

We present an overview of some recent developments in the theoretical modeling of transition-metal systems, particularly the ultrathin-film structures, focusing on the effects of electron-electron interactions. We describe the progress in the understanding of how to model realistic strongly correlated electron systems using and going beyond the local-density-approximation single-particle electronic structures. Results of exact many-body calculations of photoemission and inverse photoemission spectra of ultrathin nickel, iron and cobalt films are shown to illustrate the application of our approach. Interesting new features induced by many-body effects are found and discussed. Comparison with available experimental results is presented and further work, both experimental and theoretical, is suggested.

Exact Diagonalization Study of Real Materials

1992 ◽  
Vol 291 ◽  
Author(s):  
Changfeng Chen
Keyword(s):  
High Performance ◽  
Local Density ◽  
Spectroscopic Properties ◽  
Strongly Correlated ◽  
Many Body ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron ◽  
Recent Developments ◽  
Body Correlation

ABSTRACTWe report some recent developments in theoretical modeling of real 3d magnetic materials, particularly interface and ultrathin-film structures. We focus on many-body correlation effects and describe the method of modeling realistic strongly correlated electron systems using and going beyond die local-density-approximation single-particle electronic structures. Group-theoretical techniques and high-performance computing facilities are systematically used in this work. Fundamental spectroscopic properties of several prototypical 3d transition-metal systems have been obtained and new features induced by many-body correlation have been discovered. Results will be presented and discussed.

scholarly journals REALISTIC MODELING OF STRONGLY CORRELATED ELECTRON SYSTEMS: AN INTRODUCTION TO THE LDA+DMFT APPROACH

2001 ◽  
Vol 15 (19n20) ◽  
pp. 2611-2625 ◽  
Author(s):  
K. HELD ◽  
I. A. NEKRASOV ◽  
N. BLÜMER ◽  
V. I. ANISIMOV ◽  
D. VOLLHARDT
Keyword(s):  
Quantum Monte Carlo ◽  
Local Density ◽  
Mean Field Theory ◽  
Mean Field ◽  
Structure Theory ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron ◽  
Basic Ideas ◽  
Set Up

The LDA+DMFT approach merges conventional band structure theory in the local density approximation (LDA) with a state-of-the-art many-body technique, the dynamical mean-field theory (DMFT). This new computational scheme has recently become a powerful tool for ab initio investigations of real materials with strong electronic correlations. In this paper an introduction to the basic ideas and the set-up of the LDA+DMFT approach is given. Results for the photoemission spectra of the transition metal oxide La 1-x Sr x TiO 3, obtained by solving the DMFT equations by quantum Monte Carlo (QMC) simulations, are presented and are found to be in very good agreement with experiment. The numerically exact DMFT(QMC) solution is compared with results obtained by two approximative solutions, i.e. the iterative perturbation theory and the non-crossing approximation.

DYNAMICS OF HOLES IN THE Cu-OXIDE SUPERCONDUCTORS

1989 ◽  
Vol 03 (16) ◽  
pp. 1191-1195 ◽  
Author(s):  
J. INOUE ◽  
S. MAEKAWA
Keyword(s):  
Valence Bond ◽  
Oxide Superconductors ◽  
Strongly Correlated ◽  
Electron Systems ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron ◽  
Bond State ◽  
Recent Developments ◽  
The Stability

Recent developments of our work on the dynamics of holes in strongly correlated electron systems and on the stability of the resonating valence bond state are summarized.

scholarly journals Many-body effects on the resistivity of a multi-orbital system beyond Landau's Fermi-liquid theory

2015 ◽  
Vol 29 (15) ◽  
pp. 1530005 ◽  
Author(s):  
Naoya Arakawa
Keyword(s):  
Temperature Dependence ◽  
Fermi Liquid ◽  
Quantum Critical Point ◽  
Electron Systems ◽  
Many Body ◽  
Correlated Electron Systems ◽  
Orbital System ◽  
Self Energy ◽  
Correlated Electron ◽  
Many Body Effects

I review many-body effects on the resistivity of a multi-orbital system beyond Landau's Fermi-liquid (FL) theory. Landau's FL theory succeeds in describing electronic properties of some correlated electron systems at low temperatures. However, the behaviors deviating from the temperature dependence in the FL, non-FL-like behaviors, emerge near a magnetic quantum-critical point (QCP). These indicate the importance of many-body effects beyond Landau's FL theory. Those effects in multi-orbital systems have been little understood, although their understanding is important to deduce ubiquitous properties of correlated electron systems and characteristic properties of multi-orbital systems. To improve this situation, I formulate the resistivity of a multi-orbital Hubbard model using the extended Éliashberg theory and adopt this method to the inplane resistivity of quasi-two-dimensional paramagnetic ruthenates in combination with the fluctuation-exchange approximation including the current vertex corrections arising from the self-energy and Maki–Thompson term. The results away from and near the antiferromagnetic QCP reproduce the temperature dependence observed in Sr 2 RuO 4 and Sr 2 Ru 0.075 Ti 0.025 O 4, respectively. I highlight the importance of not only the momentum and the temperature dependence of the damping of a quasiparticle but also its orbital dependence in discussing the resistivity of correlated electron systems.

scholarly journals QUASIPARTICLE MANY-BODY DYNAMICS OF THE ANDERSON MODEL

1996 ◽  
Vol 10 (15) ◽  
pp. 1895-1912 ◽  
Author(s):  
A.L. KUZEMSKY
Keyword(s):  
General Scheme ◽  
Coulomb Repulsion ◽  
Dyson Equation ◽  
Many Body ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Self Energy ◽  
Correlated Electron ◽  
The Many ◽  
The One

The paper addresses the many-body quasiparticle dynamics of the Anderson impurity model at finite temperatures in the framework of the equation-of-motion method. We find a new exact identity relating the one-particle and many-particle Green’s functions. Using this identity we present a consistent and general scheme for a construction of generalized mean fields (elastic scattering corrections) and self-energy (inelastic scattering) in terms of Dyson equation. A new approach for the complex expansion for the single-particle propagator in terms of Coulomb repulsion U and hybridization V is proposed. Using the exact identity, the essentially new many-body dynamical solution of SIAM has been derived. This approach offers a new way for the systematic construction of the approximative interpolating dynamical solutions of the strongly correlated electron systems.

Strongly correlated superconductivity

2018 ◽  
Vol 32 (17) ◽  
pp. 1840023
Author(s):  
T. Yanagisawa ◽  
M. Miyazaki ◽  
K. Yamaji
Keyword(s):  
High Temperature Superconductivity ◽  
Strongly Correlated ◽  
Electron Systems ◽  
Many Body ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron ◽  
Repulsive Coulomb ◽  
Variational Monte Carlo Method ◽  
The Many

We investigate the electronic properties of the ground state of strongly correlated electron systems. We use an optimization variational Monte Carlo method for the two-dimensional Hubbard model and the three-band d-p model. The many-body wavefunction is improved and optimized by introducing variational parameters that control the correlation between electrons. The on-site repulsive Coulomb interaction U induces strong antiferromagnetic (AF) correlation. There is a crossover from weakly to strongly correlated regions as U increases. We show an idea that high-temperature superconductivity occurs as a result of this crossover in the strongly correlated region where U is greater than the bandwidth.

scholarly journals Propagation of shear stress in strongly interacting metallic Fermi liquids enhances transmission of terahertz radiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
D. Valentinis ◽  
J. Zaanen ◽  
D. van der Marel
Keyword(s):  
Shear Stress ◽  
Terahertz Radiation ◽  
Fermi Liquid ◽  
Zero Sound ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron ◽  
Collisionless Regime ◽  
Propagating Shear ◽  
Mass Enhancement

AbstractA highlight of Fermi-liquid phenomenology, as explored in neutral $$^3$$ 3 He, is the observation that in the collisionless regime shear stress propagates as if one is dealing with the transverse phonon of a solid. The existence of this “transverse zero sound” requires that the quasiparticle mass enhancement exceeds a critical value. Could such a propagating shear stress also exist in strongly correlated electron systems? Despite some noticeable differences with the neutral case in the Galilean continuum, we arrive at the verdict that transverse zero sound should be generic for mass enhancement higher than 3. We present an experimental setup that should be exquisitely sensitive in this regard: the transmission of terahertz radiation through a thin slab of heavy-fermion material will be strongly enhanced at low temperature and accompanied by giant oscillations, which reflect the interference between light itself and the “material photon” being the actual manifestation of transverse zero sound in the charged Fermi liquid.

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