Related papers: Phase separation in double exchange systems
We study electronic properties of AA-stacked graphene bilayers. In the single-particle approximation such a system has one electron band and one hole band crossing the Fermi level. If the bilayer is undoped, the Fermi surfaces of these…
In superconducting ferromagnets for which the Curie temperature $T_{m}$ exceeds the superconducting transition temperature $T_{c}$, it was suggested that ferromagnetic spin fluctuations could lead to superconductivity with p-wave spin…
The magnetic excitation spectrum in the two-dimensional (2D) S=1/2 Heisenberg antiferromagnet copper deuteroformate tetradeuterate (CFTD) has been measured for temperatures up to T\sim J/2, where J=6.31+-0.02 meV is the 2D exchange…
We study the boundary between ferromagnetic and non-ferromagnetic ground state of a double-exchange system with quenched disorder for arbitrary relation between Hund exchange coupling and electron band width. The boundary is found both from…
We present extensive large-scale dynamical simulations of phase-separated states in the double exchange model. These inhomogeneous electronic states that play a crucial role in the colossal magnetoresistance phenomenon are composed of…
A review of the present state of investigations of the pseudospin-electron model (PEM), which is used in the theory of strongly correlated electron systems, is given. The model is used to describe the systems with the locally anharmonic…
The magnetic excitations of the double exchange (DE) model are usually discussed in terms of an equivalent ferromagnetic Heisenberg model. However this equivalence is valid only at a quasi--classical level - we show that both quantum and…
Exact thermal studies of small (4-site, 5-site and 8-site) Hubbard clusters with local electron repulsion yield intriguing insight into phase separation, charge-spin separation, pseudogaps, condensation, in particular, pairing fluctuations…
An isotropic half-metallic double exchange magnet with a direct superexchange coupling between the localized spins is studied within the spin-wave (1/S) expansion. The momentum dependence of the spin wave spectrum (including quantum…
The main features of a generic boson-fermion scenario for electron pairing in a many-body correlated fermionic system are: i) a cross-over from a poor metal to an insulator and finally a superconductor as the temperature decreases, ii) the…
A double-exchange mechanism for the emergence of ferromagnetism in cubic uranium compounds is proposed on the basis of a $j$-$j$ coupling scheme. The idea is {\it orbital-dependent duality} of $5f$ electrons concerning itinerant…
We study superconductivity in paramagnetic and ferromagnetically-ordered phases in a two-dimensional electron system with parabolic fermionic dispersion and short-range repulsive interaction. In the paramagnetic phase, we find that a weak…
Starting from a spin-fermion model for the cuprate superconductors, we obtain an effective interaction for the charge carriers by integrating out the spin degrees of freedom. Our model predicts a quantum critical point for the…
Bipolar carrier transport is often a limiting factor in the thermoelectric efficiency of narrow bandgap materials at high temperatures due to the reduction in the Seebeck coefficient and the introduction of an additional term to the thermal…
We propose a model of carrier-mediated ferromagnetism in semiconductors that accounts for the temperature dependence of the carriers. The model permits analysis of the thermodynamic stability of competing magnetic states, opening the door…
Thermodynamic properties of a tetrameric bond-alternating Heisenberg spin chain with ferromagnetic-ferromagnetic-antiferromagnetic-antiferromagnetic exchange interactions are studied using the transfer-matrix renormalization group and…
The effect of binary alloy disorder on the ferromagnetic phases of f-electron materials is studied within the periodic Anderson model. We find that disorder in the conduction band can drastically enhance the Curie temperature due to an…
Employing the Monte-Carlo method and the exact diagonalization, we have investigated the temperature dependence of the thermoelectric power (TEP) for the double exchange model in the dilute carrier concentration limit. We have found that…
We investigate the emergence of ferromagnetism in the two-dimensional metal-halide CoBr$_2$, with a special focus on the role of electronic correlations. The calculated phonon spectrum shows that the system is thermodynamically stable…
Magnetization switching in ferromagnets has so far been limited to the current-induced spin-orbit-torque effects. Recent observation of helicity-independent all-optical magnetization switching in exchange-coupled ferromagnet ferrimagnet…