Related papers: Dynamical correlations in half-metallic manganites
A novel approach to electronic correlations in magnetic crystals which takes into account a dynamical many-body effects is present. In order to to find a frequency dependence of the electron self energy, an effective quantum-impurity…
The two-dimensional extended Hubbard model that includes a nearest- neighbor Heisenberg interaction is studied using a mean-field theory where quasiparticles are defined by an U(8) group of canonical transformations. The theory is a…
We investigate the electronic properties of multi-domain configurations in models for undoped manganites by means of variational and Monte Carlo techniques. These materials display simultaneous Jahn-Teller distortions and magnetic ordering.…
We use neutron scattering to investigate the doping evolution of the magnetic correlations in the single-layer manganite $\rm Pr_{\it 1-x}Ca_{\it 1+x}MnO_4$, away from the $x=0.5$ composition where the CE-type commensurate antiferromagnetic…
Strong electron-electron interactions are known to significantly modify the electron-phonon coupling relative to the predictions of density functional theory, but this effect is challenging to calculate with realistic theories of strongly…
We present a mean-field approach for accurately describing strong correlations via electron number fluctuations and pairings constrained to an active space. Electron number conservation is broken and correct only on average but both spin…
Dimensionality and electronic correlations are crucial elements of many quantum material properties. An example is the change of the electronic structure accompanied by the loss of quasiparticles when a metal is reduced from three…
Recent experimental study reveals the optical conductivity of La$_{1-x}$Ca$_x$MnO$_3$ over a wide range of energy and the occurrence of spectral weight transfer as the system transforms from paramagnetic insulating to ferromagnetic metallic…
We review some aspects related to orbital degrees of freedom in manganites. The Mn$^{3+}$ ions in these compounds have double orbital degeneracy and are strong Jahn-Teller ions, causing structural distortions and orbital ordering. We…
The interplay of light and matter gives rise to intriguing cooperative effects in quantum many-body systems. This is even true in thermal equilibrium, where the electromagnetic field can hybridize with collective modes of matter, and…
We study the effect of spin-orbit interaction and in-plane effective magnetic field on the conductance of a quasi-one-dimensional ballistic electron system. The effective magnetic field includes the externally applied field, as well as the…
Graphene is an ideal platform to study many-body effects due to its semimetallic character and the possibility to dope it over a wide range. Here we study the width of graphene's occupied $\pi$-band as a function of doping using…
We study finite-temperature properties of ultracold four-component mixtures of alkaline-earth-like atoms in optical lattices that can be effectively described by the two-band spin-$1/2$ Hubbard model including the Hund's exchange coupling…
We derive an effective Hamiltonian for highly correlated $t_{2g}$ states centered at the Co sites of Na$_x$CoO$_2$. The essential ingredients of the model are an O mediated hopping, a trigonal crystal-field splitting, and on-site effective…
We study a two-band Hubbard model using the dynamical mean-field theory combined with the exact diagonalization method. At the electron density $n=2$, a transition from a band-insulator to a correlated semimetal occurs when the on-site…
The effects of electron-electron correlations on the low-energy electronic structure and their relationship with unconventional superconductivity are central aspects in the research on the iron-based pnictide superconductors. Here we use…
We propose a formalism to take account of the correction of the spatial fluctuations to the local self-energy obtained by the dynamical mean-field approximation. For this purpose, the approximate dynamical susceptibility in the framework of…
We study the evolution of the optical conductivity in the t-J model with temperature and doping using the Extended Dynamical Cluster Approximation. The cluster approach results in an optical mass which is doping independent near half…
We investigate low-temperature electronic states of the series of organic conductors $\beta^{\prime\prime}$-(BEDT-TTF)$_4$[(H$_3$O)M(C$_2$O$_4$)$_3$]G, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene, and M and G represent trivalent…
Understanding the coexistence of ferromagnetism and insulating behavior in manganites is an unsolved problem. We propose a localized-band model involving effective intermediate-range electron-electron (electron-hole) repulsion (attraction)…