Related papers: Polaron Exchange Model for Ferromagnetic Ordering …
Unrestricted Hartree-Fock calculations on La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3 in the full magnetic unit cell show that the magnetic ground states of these compounds consist of 'ferromagnetic molecules' or polarons ordered in herring-bone…
Using the Lanczos method in linear chains we study the ground state of the double exchange model including an antiferromagnetic super-exchange in the low concentration limit. We find that this ground state is always inhomogeneous, containig…
Impurity effects on the stability of a ferromagnetic metallic state in a bicritical-state manganite, (La0.7Pr0.3)0.65Ca0.35MnO3, on the verge of metal-insulator transition have been investigated by substituting a variety of transition-metal…
Neutron scattering has been used to study the nature of the ferromagnetic transition in a single crystal of the perovskite La0.7Ca0.3MnO3. Diffuse scattering from lattice polarons develops as the Curie temperature is approached from below,…
We theoretically study the heat flux between electrons and phonons in a thin metallic film embedded in a suspended dielectric slab (called a \textit{membrane}, in accordance with the established nomenclature), forming a layered structure.…
In view of recent experiments, indicating the spatial coexistence of conducting and insulating regions in the ferromagnetic metallic phase of doped manganites, we propose a refined mixed-phase description. The model is based on the…
There is a growing understanding that transport properties of complex oxides and individual molecules are dominated by polaron physics. In superconducting oxides the long-range Froehlich and short-range Jahn-Teller electron-phonon…
We report x-ray scattering studies of broad peaks located at a (0.5 0 0)/(0 0.5 0)-type wavevector in the paramagnetic insulating phases of La_{0.7}Ca_{0.3}MnO_{3} and Pr_{0.7}Ca_{0.3}MnO_{3}. We interpret the scattering in terms of…
Lead halide perovskite semiconductors are soft, polar, materials. The strong driving force for polaron formation (the dielectric electron-phonon coupling) is balanced by the light band effective-masses, leading to a strongly-interacting…
The optical conductivity of charge carriers coupled to quantum phonons is studied in the framework of the one-dimensional spinless Holstein model. For one electron, variational diagonalisation yields exact results in the thermodynamic…
A single electron in one dimensional lattice is considered within the framework of extended Holstein model at strong-coupling limit. Disordered density-displacement type electron-phonon interaction is proposed. Basic parameters of small…
Recent research suggests that the charge carriers in the paramagnetic state of the magnetoresistive manganites are small polarons. Here we report studies of the oxygen-isotope effects on the intrinsic resistivity and thermoelectric power in…
Mott insulators based on $4d$ and $5d$ transition-metal ions, where spin-orbit interaction plays a key role, can exhibit various forms of unusual magnetism. A particular example is the antiferromagnet Ca$_2$RuO$_4$ containing $d^4$…
The electronic density of states (DOS) of La$_{0.625}$Ca$_{0.375}$MnO$_3$(LCMO) strain free epitaxial thin films with an insulator-metal transition temperature (T$_{IM}$) of 250 K was probed using variable temperature scanning tunneling…
Ferroelectrics feature spontaneous electric dipolar order reconfigurable via electric fields. Recent theoretical studies of the collective excitations of this electric dipolar order give rise to the hope that "ferron" quasiparticles may…
The transport and magnetic properties in ferromagnetic manganese-oxide thin films are studied based on the model of the coupling between the mobile d-electrons and the core spins in Mn ions. The spontaneous magnetization and the resistivity…
We study paramagnetic - ferromagnetic transition due to exchange interaction between classical localized magnetic moments and conduction electrons. We formulate the Dynamical Mean Field Approximation equations for arbitrary electron…
Based on the Holstein double-exchange model and a highly efficient single cluster Monte Carlo approach we study the interplay of double-exchange and polaron effects in doped colossal magneto-resistance (CMR) manganites. The CMR transition…
We analyze the heat power $P$ between electrons and phonons in thin metallic films deposited on free-standing dielectric membranes in a temperature range in which the phonon gas has a quasi two-dimensional distribution. The quantization of…
We present a study of the magnetic properties of the electron doped manganites Ca1-xYxMnO3 (for 0<=x<=0.25) in the paramagnetic regime. For the less doped samples (x<=0.1) the magnetic susceptibility, c(T), follows a Curie-Weiss (CW) law…