Related papers: Jahn-Teller effect and Electron correlation in man…
We investigate the effect of strong electron-electron repulsion on the electron-phonon interaction from a Fermi-liquid point of view: the strong interaction is responsible for vertex corrections, which are strongly dependent on the…
The origin of the cooperative Jahn-Teller distortion and orbital-order in LaMnO3 is central to the physics of the manganites. The question is complicated by the simultaneous presence of tetragonal and GdFeO3-type distortions and the strong…
The electronic self-energy is studied for a two dimensional electron gas coupled to a spin-orbit Rashba field and interacting with dispersionless phonons. For the case of a momentum independent electron-phonon coupling (Holstein model) we…
A C$_3$-symmetric crystal-field potential in the Fe(II)Fe(III) bimetallic oxalates splits the L=2 Fe(II) multiplet into two doublets and a singlet. In compounds that exhibit magnetic compensation, one of the doublets was predicted to lie…
Motivated by the observation in copper-oxide high-temperature superconductors, we investigate the appearance of kinks in the electronic dispersion due to coupling to phonons for a system with strong electronic repulsion. We study a Hubbard…
A recursive method is developed to treat electrons coupled to phonons. It is applied to small systems with $E\otimes\beta$ Jahn-Teller coupling. Two cases are considered, a model with one electron and two orbitals on a single site (related…
The ground state energy shifts and excitation spectra of charged buckminsterfullerene C$_{60}^{n-}$, $n=1,\ldots 5$ are calculated. The electron--vibron Hamiltonian of Part I is extended to include all $A_g$ and $H_g$ modes with…
The complex interplay of charge, spin, orbital, and lattice degrees of freedom governs emergent phases in quantum materials, making strain a powerful control parameter. Recent advances in free-standing layer techniques have enabled extreme…
The persistent proximity of insulating and metallic phases, a puzzling characterestic of manganites, is argued to arise from the self organization of the twofold degenerate e_g orbitals of Mn into localized Jahn-Teller(JT) polaronic levels…
We investigated slow relaxations of the magnetostriction and residual magnetostriction of the phase-separated system (Eu$_{1-x}$Gd$_{x}$)$_{0.6}$Sr$_{0.4}$MnO$_3$, in which the metamagnetic transition from a paramagnetic insulating state to…
We study acoustic-phonon-induced relaxation of charge excitations in single and tunnel-coupled quantum dots containing few confined interacting electrons. The Full Configuration Interaction approach is used to account for the…
We study the isotope effects arising from the coupling of correlated electrons with dispersionless phonons by considering the Hubbard-Holstein model at half-filling within the dynamical mean-field theory. In particular we calculate the…
With increasing electron-phonon coupling as described within the t-J-Holstein model, bipolaron kinetic energy is lowered in comparison with that of the polaron. This effect is accompanied with "undressing" of bipolaron from lattice degrees…
Resonant behavior of the Raman process is predicted when the laser frequency is close to the orbital excitation energy of LaMnO3 at 2 eV. The incident photon creates a vibrationally excited self-trapped ``orbiton'' state from the…
Structural phase transition studies employing low-temperature transmission electron microscopy, and low-temperature x-ray diffraction have been carried out on nearly stoichiometric ({\delta}=0.01) and off-stoichiometric ({\delta}=0.12)…
Doped and undoped manganites are modeled by the coupling between itinerant $e_g$ electrons and static $t_{2g}$ spins, the Jahn-Teller and breathing phonon modes, and the Coulomb interaction. We provide for a careful estimate of all…
The strong-coupling perturbation theory (SCPT) for correlated electron systems is extended to the case of full Coulomb interaction. The Coulomb mechanism of the orbital polarization is discussed and attention is paid to the importance of…
We examine the interplay between electron correlations and phonons in an Anderson-Holstein impurity model with an Einstein phonon. When the phonons are slow compared to charge fluctuations (frequency $\omega_0 \ll U/2$, the onsite Coulomb…
We have derived the interaction between Jahn-Teller centers due to optical and acoustic phonons. Without Coulomb repulsion the model leads to a global phase separation at low temperature. At long distances Coulomb repulsion always dominates…
The interactions between $e_g$ orbitals in neighboring sites are investigated in LaMnO$_3$ by taking into account virtual exchange of electrons and phonons. The spin and orbital ordering temperatures and the spin wave dispersion relation…