The spin-polaron concept in the theory of normal and superconducting states of cuprate

2020 ◽  
Author(s):  
Valerii V. Val'kov ◽  
Dmitrii M. Dzebisashvili ◽  
Maksim M. Korovushkin ◽  
Aleksandr F. Barabanov
Keyword(s):  
Spin Polaron

Strong Coupling of Electron and Nuclear Spins: Outlook and Prospects

2018 ◽  
Author(s):  
M. M. Glazov
Keyword(s):  
Energy Spectrum ◽  
Charge Carrier ◽  
Strong Coupling ◽  
Nuclear Spin ◽  
Spin Dynamics ◽  
Spin Polaron ◽  
Nuclear Spins ◽  
Deep Impurity ◽  
Impurity Centers ◽  
Ordered State

In this chapter, some prospects in the field of electron and nuclear spin dynamics are outlined. Particular emphasis is put ona situation where the hyperfine interaction is so strong that it leads to a qualitative rearrangement of the energy spectrum resulting in the coherent excitation transfer between the electron and nucleus. The strong coupling between the spin of the charge carrier and of the nucleus is realized, for example in the case of deep impurity centers in semiconductors or in isotopically purified systems. We also discuss the effect of the nuclear spin polaron, that is ordered state, formation at low enough temperatures of nuclear spins, where the orientation of the carrier spin results in alignment of the spins of nucleus interacting with the electron or hole.

Time dynamics of spins-fermional models in Cu2O

2021 ◽  
pp. 110-113
Author(s):  
V.S. Kirchanov ◽  
Keyword(s):  
System Of Equations ◽  
Spin Polaron ◽  
Harmonic Oscillations ◽  
Fermion Model ◽  
Time Dynamics ◽  
Coupling Operator ◽  
Frequency Harmonic

The solution of the system of equations for the basic operators of the spin-fermion model is obtained in the form of harmonic oscillations of Fermi operators at two frequencies, and three-frequency harmonic oscillations of the spin-fermion coupling operator (spin-polaron).

scholarly journals Описание колоссального магнитосопротивления La-=SUB=-1.2-=/SUB=-Sr-=SUB=-1.8-=/SUB=-Mn-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- на основе "спин-поляронного" и "ориентационного" механизмов проводимости в парамагнитной области температур

2020 ◽  
Vol 62 (5) ◽  
pp. 669
Author(s):  
С.А. Гудин ◽  
Н.И. Солин
Keyword(s):  
Magnetic Field ◽  
Colossal Magnetoresistance ◽  
Main Role ◽  
Spin Polaron ◽  
Temperature Range ◽  
Conduction Mechanisms ◽  
Theoretical Investigations ◽  
Temperature Dependences ◽  
The Magnetic Field ◽  
Good Agreement

Experimental and theoretical investigations of the resistance of the La1.2Sr1.8Mn2O7 single crystal in magnetic fields from 0 to 90 kOe and in the temperature range from 75 to 300 K has been studied. The magnetoresistance is determined by the “spin-polaron” and “orientation” conduction mechanisms. Using the method of separating contributions to the magnetoresistance from several conduction mechanisms, the observed magnetoresistance of La1.2Sr1.8Mn2O7 manganite in the temperature range of 75-300 K is described, good agreement between the calculated and experimental data is obtained. In a magnetic field of 0 and 90 kOe, the temperature dependences of the size of the spin polaron (in relative units) are calculated for the temperature range 75–300 K. It is shown, that the КМС value is determined by an increase in the linear size of the spin polaron (along the magnetic field), i.e. the main role in the magnitude of the colossal magnetoresistance is made by the change in the size of the magnetic inhomogeneities of the crystal.

THE ROLE OF THE GHOST FIELDS IN THE RENORMALIZED t–J LAGRANGIAN MODEL

2009 ◽  
Vol 23 (04) ◽  
pp. 493-519
Author(s):  
O. S. ZANDRON
Keyword(s):  
Thermal Softening ◽  
Lagrangian Model ◽  
Lagrangian Formalism ◽  
Spin Polaron ◽  
Renormalization Procedure ◽  
Ghost Field

The present work treats the role of ghost fields in the renormalization procedure of the Lagrangian perturbative formalism of the t–J model. We show that by introducing proper ghost field variables, the propagators and vertices can be renormalized to each order. In particular, the renormalized ferromagnetic magnon propagator coming from our previous Lagrangian formalism is studied in detail, and it is shown how the thermal softening of the magnon frequency is predicted by the model. The antiferromagnetic case is also analyzed, and the results are confronted with the previous one obtained by means of the spin-polaron theories.

scholarly journals Spin-polaron formation and magnetic state diagram in La-doped CaMnO3

2017 ◽  
Vol 95 (22) ◽  
Author(s):  
N. Bondarenko ◽  
Y. Kvashnin ◽  
J. Chico ◽  
A. Bergman ◽  
O. Eriksson ◽  
...  
Keyword(s):  
Magnetic State ◽  
State Diagram ◽  
Spin Polaron ◽  
Polaron Formation ◽  
La Doped

PREDATION AND STEADY STATES IN HIGH-TC SUPERCONDUCTORS

1993 ◽  
Vol 07 (12) ◽  
pp. 829-833
Author(s):  
RONALDO MOTA
Keyword(s):  
Steady State ◽  
Steady States ◽  
Dynamical Model ◽  
Stable Steady State ◽  
Spin Polaron ◽  
High Tc Superconductors ◽  
High Tc ◽  
Practical Model

A study of the role played by predation in a population dynamical model previously considered for spin-polaron-pairs in high-Tc superconductors is presented. A practical model which exhibits two positive linearly stable steady state populations is considered. A discussion of various aspects and implications of the model is given.

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