scholarly journals Electron liquid state in the symmetric Anderson lattice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Igor N. Karnaukhov
Keyword(s):  
Low Temperatures ◽  
Arbitrary Dimension ◽  
Mean Field ◽  
Coulomb Repulsion ◽  
Anomalous Behavior ◽  
Effective Field ◽  
Kondo Lattice ◽  
Field Approach ◽  
Cubic Lattices ◽  
Half Filling

AbstractUsing mean field approach, we provide analytical and numerical solution of the symmetric Anderson lattice for arbitrary dimension at half filling. The symmetric Anderson lattice is equivalent to the Kondo lattice, which makes it possible to study the behavior of an electron liquid in the Kondo lattice. We have shown that, due to hybridization (through an effective field due to localized electrons) of electrons with different spins and momenta $$\mathbf{k} $$ k and $$\mathbf{k} +\overrightarrow{\pi }$$ k + π → , the gap in the electron spectrum opens at half filling. Such hybridization breaks the conservation of the total magnetic momentum of electrons, the spontaneous symmetry is broken. The state of electron liquid is characterized by a large Fermi surface. A gap in the spectrum is calculated depending on the magnitude of the on-site Coulomb repulsion and value of s–d hybridization for the chain, as well as for square and cubic lattices. Anomalous behavior of the heat capacity at low temperatures in the gapped state, which is realized in the symmetric Anderson lattice, was also found.

scholarly journals Electron Liquid State in the Symmetric Anderson Lattice

2020 ◽  
Author(s):  
Igor Karnaukhov
Keyword(s):  
Fermi Surface ◽  
Liquid State ◽  
Arbitrary Dimension ◽  
Mean Field ◽  
Coulomb Repulsion ◽  
Effective Field ◽  
Kondo Lattice ◽  
Field Approach ◽  
Cubic Lattices ◽  
Half Filling

Abstract Using mean field approach, we provide analytical and numerical solution of the symmetric Anderson lattice for arbitrary dimension at half filling. The symmetric Anderson lattice is equivalent to the Kondo lattice, which makes it possible to study the behavior of an electron liquid in the Kondo lattice. We have shown that, due to hybridization (through an effective field due to localized electrons) of electrons with different spins and momenta k and k+→π, the gap in the electron spectrum opens at half filling. Such hybridization breaks the conservation of the total magnetic momentum of electrons, the spontaneous symmetry is broken. The state of electron liquid is characterized by a large Fermi surface. A gap in the spectrum is calculated depending on the magnitude of the on-site Coulomb repulsion and value of s-d hybridization for the chain, as well as for square and cubic lattices.

scholarly journals Phase transition induced by an external field in a three-dimensional isotropic Heisenberg antiferromagnet

2018 ◽  
Vol 32 (32) ◽  
pp. 1850390
Author(s):  
Minos A. Neto ◽  
J. Roberto Viana ◽  
Octavio D. R. Salmon ◽  
E. Bublitz Filho ◽  
José Ricardo de Sousa
Keyword(s):  
Magnetic Field ◽  
Mean Field ◽  
Three Dimensional ◽  
Effective Field ◽  
The Body ◽  
Bravais Lattice ◽  
Body Centered Cubic ◽  
Cubic Lattice ◽  
Cubic Lattices ◽  
Simple Cubic

The critical frontier of the isotropic antiferromagnetic Heisenberg model in a magnetic field along the z-axis has been studied by mean-field and effective-field renormalization group calculations. These methods, abbreviated as MFRG and EFRG, are based on the comparison of two clusters of different sizes, each of them trying to mimic a specific Bravais lattice. The frontier line in the plane of temperature versus magnetic field was obtained for the simple cubic and the body-centered cubic lattices. Spin clusters with sizes N = 1, 2, 4 were used so as to implement MFRG-12, EFRG-12 and EFRG-24 numerical equations. For the simple cubic lattice, the MFRG frontier exhibits a notorious re-entrant behavior. This problem is improved by the EFRG technique. However, both methods agree at lower fields. For the body-centered cubic lattice, the MFRG method did not work. As in the cubic lattice, all the EFRG results agree at lower fields. Nevertheless, the EFRG-12 approach gave no solution for very low temperatures. Comparisons with other methods have been discussed.

Mean-field solution of the Kondo lattice away from half-filling

1999 ◽  
Vol 259-261 ◽  
pp. 181-182
Author(s):  
A Ruppenthal ◽  
J.R Iglesias ◽  
M.A Gusmão
Keyword(s):  
Mean Field ◽  
Kondo Lattice ◽  
Field Solution ◽  
Half Filling

Study of frequency- and temperature-dependent electrical transport in heavy fermion systems

2017 ◽  
Vol 31 (12) ◽  
pp. 1750081 ◽  
Author(s):  
P. C. Baral
Keyword(s):  
Electrical Transport ◽  
Heavy Fermion ◽  
Mean Field ◽  
Coulomb Repulsion ◽  
Kondo Lattice ◽  
Mean Field Approximation ◽  
Model Parameters ◽  
Dynamical Response ◽  
Electrical Transport Properties ◽  
Temperature Dependent

This paper focuses on the frequency- and temperature-dependent electrical transport properties of heavy fermion (HF) systems. For this, Kondo lattice model (KLM) with Coulomb correlation between [Formula: see text]–[Formula: see text] electrons at the same site is considered. The Hamiltonian is treated in mean-field approximation (MFA) for the Kondo hybridization and Heisenberg-type interaction to get mean-field Hamiltonian and it is written after the Fourier transformation. The Hartree–Fock-type approximation is considered for the Coulomb repulsion between [Formula: see text]–[Formula: see text] electrons, the perturbed part of the Hamiltonian. The two Green’s functions for the conduction and [Formula: see text]-electrons are calculated to define the self-energy. Then the frequency- and temperature-dependent optical conductivity and resistivity are calculated by using the Kubo’s formula within the linear dynamical response approach. They are studied by varying the model parameters. The anomalies and results obtained are compared with experimental data.

Mean-Field Analysis of the Three-Band Hubbard Model

1998 ◽  
Vol 12 (27n28) ◽  
pp. 2831-2845 ◽  
Author(s):  
Yabin Yu ◽  
Guanghan Cao ◽  
Zhengkuan Jiao
Keyword(s):  
Electronic Structure ◽  
Hubbard Model ◽  
Singlet State ◽  
Mean Field ◽  
Coulomb Repulsion ◽  
Mean Field Approximation ◽  
Band Model ◽  
Spin Singlet ◽  
Half Filling ◽  
The Mean

A full three-band model for the CuO 2 plane of cuprates, which includes all the essential interaction — Cu-O and O-O hopping and the Coulomb repulsion on the Cu and O sites and between them, is considered. Its antiferromagnetic ground state for the half-filling is studied by using the mean field approximation. The electronic structure and the magnetic properties such as the densities of states, the energy spectra, the composition of holes (Cu or O character), the superexchange interaction and the magnetic moment are calculated and in general, our results are in agreement with the available experimental and other calculation results. Meanwhile, we find that the influence of the O-O hopping and Cu-O intrasite Coulomb repulsion on these properties is considerable. Our estimate of the energy of the spin singlet state above the antiferromagnetic background indicates that the lowest excitation state of the holes is the singlet state and give a charge-transfer energy in agreement with the experiment. We also discuss the hole-doping to the antiferromagnetic background and find the mean field approach invalid. Finally, based on the electronic structure at the half-filling, en effective one-band Hubbard model is presented and the effective parameters are close to the values given by the computation on the clusters.

scholarly journals Effect of band filling in the Kondo lattice: A mean-field approach

1999 ◽  
Vol 60 (10) ◽  
pp. 7321-7327 ◽  
Author(s):  
A. R. Ruppenthal ◽  
J. R. Iglesias ◽  
M. A. Gusmão
Keyword(s):  
Mean Field ◽  
Kondo Lattice ◽  
Field Approach ◽  
Band Filling

STABILITY AND SPIN DENSITY WAVE IN POLYMERIC HUBBARD CHAINS

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2586-2591 ◽  
Author(s):  
Y. F. DUAN ◽  
Z. L. LIU ◽  
K. L. YAO
Keyword(s):  
Spin Density ◽  
Mean Field Theory ◽  
Density Wave ◽  
Spin Density Wave ◽  
Mean Field ◽  
Coulomb Repulsion ◽  
Flat Band ◽  
Antiferromagnetic Order ◽  
Half Filling ◽  
The Mean

The ground state properties and spin-density wave of polymeric Hubbard chains are studied by means of the mean-field theory. It is shown that topological structure of the chain possesses a flat-band structure of the energy band. Our analysis shows that the on- site Coulomb repulsion of electrons in the chain leads to the coexistence of ferromagnetic and antiferromagnetic order, i,e., the ferrimagnetic order. Away from half filling, the system displays magnetic phase separation. Possible experimental realizations are suggested.

scholarly journals Phase diagram of an extended Kondo lattice model for manganites: The Schwinger-boson mean-field approach

2000 ◽  
Vol 61 (2) ◽  
pp. 1211-1217 ◽  
Author(s):  
R. Y. Gu ◽  
Z. D. Wang ◽  
Shun-Qing Shen ◽  
D. Y. Xing
Keyword(s):  
Phase Diagram ◽  
Lattice Model ◽  
Mean Field ◽  
Kondo Lattice ◽  
Field Approach ◽  
Kondo Lattice Model

Magnetic Response of Itinerant Spin Ice

SPIN ◽  
2015 ◽  
Vol 05 (02) ◽  
pp. 1540004 ◽  
Author(s):  
Masafumi Udagawa
Keyword(s):  
Low Temperatures ◽  
Magnetic Field Dependence ◽  
Mean Field Theory ◽  
Mean Field ◽  
Kondo Lattice ◽  
Dynamical Mean Field Theory ◽  
Magnetic Response ◽  
Magnetization Process ◽  
Spin Ice ◽  
Kondo Lattice Model

We have studied the magnetic response of itinerant spin ice, by applying the cluster dynamical mean field theory (CDMFT) to the Ising Kondo lattice model on a pyrochlore lattice. As a result, we found a characteristic interplay between magnetization curve and spin ice correlation developed at low temperatures. The magnetization develops a kink-like structure at the 2/3 of its saturation value, reminiscent of kagome ice plateau. Accompanied with the magnetization process, the monopole density shows nonmonotonic magnetic field dependence with a clear minimum, reflecting a subtle energetics of spin configurations. The spin ice correlation also affects the transport properties of the system, and brings about negative magnetoresistivity with its slope strongly dependent on the magnitude of spin ice correlation. We discuss these behaviors in comparison with the magnetic response observed in Pr 2 Ir 2 O 7.

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