Spin Polaron Theory for Magnetic Semiconductors with Narrow Bands

Nagaev, É.L.

doi:10.1002/pssb.2220650102

Cited by 95 publications

(45 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This direction is called zdirection hereafter and the system occupies the half-space z > 0. We use the s-f model which is commonly considered as realistic for local-moment structures 19,21,22 . In this model the following Hamiltonian is used to describe the magnetic semi-infinite crystal:…”

Section: Model and Formalismmentioning

confidence: 99%

“…Kurz et al 16 studied the magnetism and the electronic structure of Gd(0001) surface on the basis of density functional theory. Schiller et al 17,18 investigated the temperature-dependent band structure of ferromagnetic semiconductor films and surfaces in the s-f model 19 . Using a moment-conserving decoupling procedure for suitable defined Green's functions, the layer-dependent magnetizations and the LDOS were studied at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Temperature dependence of surface magnetization in local-moment systems

Saffarzadeh

2006

Surface Science

View full text Add to dashboard Cite

We present a theory to study the temperature-dependent behavior of surface states in a ferromagnetic semi-infinite crystal. Our approach is based on the single-site approximation for the s-f model. The effect of the semi-infinite nature of the crystal is taken into account by a localized perturbation method. Using the mean-field theory for the layer-dependent magnetization, the local density of states and the electron-spin polarization are investigated at different temperatures for ordinary and surface transition cases. The results show that the surface magnetic properties may differ strongly from those in the bulk and the coupling constant of atoms plays a decisive role in the degree of spin polarization. In particular, for the case in which the exchange coupling constant on the surface and between atoms in the first and second layer is higher than the corresponding in the bulk, an enhancement of surface Curie temperature and hence the spin polarization can be obtained.

show abstract

Section: Model and Formalismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Temperature dependence of surface magnetization in local-moment systems

Saffarzadeh

2006

Surface Science

View full text Add to dashboard Cite

show abstract

“…The Kondo-lattice model (or s-f model) traces back the characteristic features of the underlying physical system to an interband exchange coupling of itinerant conduction electrons to (quasi-) localized magnetic moments described by the following model Hamiltonian [5,6] …”

Section: Hamiltonianmentioning

confidence: 99%

Quantum effects in the quasiparticle structure of the ferromagnetic Kondo lattice model

Meyer¹,

Santos

Nolting

2001

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Abstract.A new "Dynamical Mean-field theory" based approach for the Kondo lattice model with quantum spins is introduced. The inspection of exactly solvable limiting cases and several known approximation methods, namely the second-order perturbation theory, the self-consistent CPA and finally a momentconserving decoupling of the equations of motion help in evaluating the new approach. This comprehensive investigation gives some certainty to our results: Whereas our method is somewhat limited in the investigation of the J < 0-model, the results for J > 0 reveal important aspects of the physics of the model: The energetically lowest states are not completely spin-polarized. A band splitting, which occurs already for relatively low interaction strengths, can be related to distinct elementary excitations, namely magnon emission (absorption) and the formation of magnetic polarons. We demonstrate the properties of the ferromagnetic Kondo lattice model in terms of spectral densities and quasiparticle densities of states.

show abstract

“…Spin-fermion model describes materials which get their magnetic properties from a system of localized magnetic moments being coupled to conducting electrons [37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Magnon-induced superconductivity in field-cooled spin-1/2 antiferromagnets

Karchev

2017

Phys. Rev. B

View full text Add to dashboard Cite

If, during the preparation, an external magnetic field is applied upon cooling we say it has been field cooled. A novel mechanism for insulator-metal transition and superconductivity in field-cooled spin-1/2 antiferromagnets on bcc lattice is discussed. Applying a magnetic field along the sublattice B magnetization, we change the magnetic and transport properties of the material. There is a critical value Hcr1. When the magnetic field is below the critical one H < Hcr1 the prepared material is a spin−1/2 antiferromagnetic insulator. When H > Hcr1 the sublattice A electrons are delocalized and the material is metal. There is a second critical value Hcr2 > Hcr1. When H = Hcr2, it is shown that the Zeeman splitting of the sublattice A electrons is zero and they do not contribute to the magnetization of the system. At this quantum partial order point (QPOP) the sublattice B transversal spin fluctuations (magnons) interact with sublattice A electrons inducing spin anti-parallel p-wave superconductivity which coexists with magnetism. At zero temperature the magnetic moment of sublattice B electrons is maximal. Below the Néel temperature (TN ) the gap is approximately constant with a small increase when the system approaches TN . It abruptly falls down to zero at temperatures above TN .

show abstract

Spin Polaron Theory for Magnetic Semiconductors with Narrow Bands

Cited by 95 publications

References 47 publications

Temperature dependence of surface magnetization in local-moment systems

Temperature dependence of surface magnetization in local-moment systems

Quantum effects in the quasiparticle structure of the ferromagnetic Kondo lattice model

Magnon-induced superconductivity in field-cooled spin-1/2 antiferromagnets

Contact Info

Product

Resources

About