目錄
1 Introduction
2 Compounds of the ReOFeAs Type
2.1 Crystallochemistry and Basic Physical Properties of Doped Compounds
2.1.1 Crystal Structure
2.1.2 Electron Doping
2.1.3 Hole Doping
2.1.4 Substitutions on the Fe Sublattice
2.1.5 Superconducting Transition Temperature
2.1.6 Critical Fields
2.1.7 Effect of Pressure on the Tc
2.2 Magnetic Properties
2.2.1 Magnetic Structure
2.2.2 Theoretical Explanation of Long-Range Magnetic Ordering in ReOFeAs
2.2.3 Phase Diagrams
2.2.4 Magnetic Fluctuations
2.3 Electronic Structure
2.3.1 Stoichiometric Compounds
2.3.2 The Role of Magnetic Ordering and Doping
2.3.3 Experimental Studies of the Fermi Surface
2.4 Symmetry of the Superconducting Order Parameter
2.4.1 Experimental Methods of Determining the Order Parameter
2.4.2 Nuclear Magnetic Resonance
2.4.3 Point-Contact Andreev Reflection
2.4.4 Tunnel and Photoemission Spectroscopies(STS, PES, ARPES)
3 Compounds of the AFeeAs2 (A = Ba,Sr, Ca) Type
3.1 Crystal and Electronic Structure
3.1.1 Crystal Structure
3.1.2 LDA Calculations of the Electronic Structure
3.1.3 Experimental Studies of the Fermi Surface
3.1.4 (Sr3Sc2Os)Fe2As2 and Other Similar Compounds
3.2 Superconductivity
3.2.1 Doping
3.2.2 Coexistence of Superconductivity and Magnetism
3.2.3 Effect of Pressure
3.2.4 Symmetry of the Superconducting Order Parameter
3.2.5 Measurements on the Josephson Contacts
3.2.6 Critical Fields
3.3 Magnetism
3.3.1 Stoichiometric Compounds
3.3.2 Doped Compounds
3.3.3 Magnetic Excitations
4 Other FeAs-Based Compounds
4.1 Compounds of the FeSe, FeTe Type
4.1.1 Superconducting Properties
4.1.2 Unusual Magnetic Properties
4.1.3 Electronic Structure of Stoichiometric Compounds
4.1.4 Electronic Structure of Doped Compounds
4.1.5 Magnetic Structure of FeTe
4.2 Compounds of the LiFeAs Type
4.2.1 Superconductivity
4.2.2 Electronic Structure
4.3 Compounds of the AFFeAs (A = St,Ca) Type
4.3.1 Primary Experimental Observations
4.3.2 Electronic Structure
5 Theory Models
5.1 General Properties of Compounds from Different Classes
of FeAs-Systems and Corresponding Theory Objectives
5.1.1 Crystal and Magnetic Structures
5.1.2 Peculiarities of the Electronic Structure
5.1.3 Asymmetry of the Electron/Hole Doping
5.1.4 Problems of Symmetry of the Superconducting Order Parameter
5.1.5 Isotopic Effect
5.2 Role of Electron Correlations
5.2.1 Dynamical Mean Field Theory (DMFT)
5.2.2 LDA+DMFT Calculation for ReOFeAs Compounds
5.2.3 LDA+DMFT Calculation on an Extended Basis
5.2.4 Comparison with Experiment
5.3 A Minimal Two-Orbital Model
5.3.1 Formulation of the Model
5.3.2 Band Structure of the Spectrum
5.3.3 Mean Field Approximation
5.3.4 Numerical Calculation for Small Clusters
5.4 Multi-Orbital Model
5.4.1 Formulation of the Model
5.4.2 Equations for a Superconductor in the Fluctuation Exchange (FLEX) Approximation
5.4.3 Properties of Superconductors with the s+ Symmetry of the Order Parameter
5.4.4 Three-Orbital Model
5.5 Detailed Analysis of the 5-Orbital Model
5.5.1 The Hamiltonian of the Model
5.5.2 Spin and Charge Susceptibility
5.5.3 Pairing of Electrons via Spin Fluctuations
5.5.4 Possible Symmetries of the Superconducting Order Parameter
5.6 Limit of Weak Coulomb Interaction
5.6.1 Renormalization Group Analysis
5.6.2 Equations for Superconducting and Magnetic Order Parameters
5.6.3 Phase Diagram of the Model
5.6.4 Peculiarities of the s~-Superconducting State
5.7 The Limit of Strong Coulomb Interaction
5.7.1 The t - J1 - J2-Model
5.7.2 Superconductivity with Different Order Parameters
5.7.3 Density of States and Differential Tunnel Conductivity
5.7.4 The Hubbard Model with the Hund's Exchange
5.8 Magnetic Long-Range Order and Its Fluctuations
5.8.1 Two Approaches to the Problem
5.8.2 The Itinerant Model
5.8.3 The Localized Model: Spin Waves
5.8.4 The Resonance Mode
5.8.5 Unified Models
5.8.6 FeAs-Compounds as Systems with Moderate Electron Correlations
5.9 Orbital Ordering
5.9.1 The Spin-Orbital Model
5.9.2 Phase Diagrams with Spin and Orbital Orderings
5.9.3 Spectrum of Magnetic Excitations
Conclusion
References
Index
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