Local and Band Characters of Strongly Correlated Electrons

Strongly correlated electrons

Strongly Correlated Electrons in Solids

Most emergent properties of the materials discovered since the 1980s are related to the existence of electronelectron interactions which are large with respect to the kinetic energies and could not be thoroughly studied before. The occurrence of metal insulator transitions, of exotic magnetic and/or superconducting properties in many new compounds have stimulated a large series of experimental ...

Quantum Magnetism Approaches to Strongly Correlated Electrons

Problems of strongly interacting electrons can be greatly simplified by reducing them to effective quantum spin models. The initial step is renormalization of the Hamiltonian into a lower energy subspace. The positive and negative U Hubbard models are explicitly transformed into the Heisenberg and -x-xz models respectively. Basic tools of quantum magnetism are introduced and used: spin coherent...

Strongly Correlated Electrons: Dynamical Vertex Renormalization

Single-band Hubbard model at criticality of the metal-insulator transition is studied using approximations derived from parquet theory. It is argued that only the electron-hole and interaction two-particle channels in the parquet algebra are relevant. A scheme is proposed how to reduce the parquet equations to a manageable form the complexity of which is comparable with single-channel approxima...

Peculiarities of the Spectrum of Strongly Correlated Electrons

Hole and spin Green’s functions of the two-dimensional t-J model of the CuO2 planes are calculated in an approximation which retains the rotation symmetry in the paramagnetic state and has no presumed magnetic ordering. In this approximation Green’s functions are represented by continued fractions which are interrupted by decouplings with a vertex correction determined from the constraint of ze...