Related papers: The Manganites as Metallic Semiconductors
The model of hypothetical superconductivity, where the energy gap asymptotically approaches zero as temperature or magnetic field increases, has been proposed. Formally the critical temperature and the second critical field for such a…
Previous theoretical studies on superconductivity were focused on the static states and adiabatic processes. Quantum mechanics simulations of time-dependent processes in superconductors were rarely performed previously. Here we use…
The metallic phase of the two-orbital Anderson lattice is study in the limit of infinite spatial dimensions, where a second order perturbation treatment is used to solve the single-site problem. Using this approximation, in the Kondo…
The highly anisotropic resistivities in strained manganites are theoretically studied using the two-orbital double-exchange model. At the nanoscale, the anisotropic double-exchange and Jahn-Teller distortions are found to be responsible for…
A new two-pole approximation, which allows to describe the transition from an insulating state to a metallic one at increase of bandwidth, and also the observable in some compounds transition from a metalic state to an insulating one with…
Single crystals of Nd_{1-x}Pb_{x}MnO_{3} with x=0.2 are grown by high temperature solution growth technique using PbO-PbF_{2} flux. Magnetization studies on the samples show a transition to a ferromagnetic state below T_c ~ 125 K and the…
Current theoretical approaches to manganites mainly stem from magnetic framework, in which the electronic transport is thought to be spin-dependent and the double exchange mechanism plays a core role. However, quite a number of experimental…
In the framework of four-band model of superconductivity in iron arsenides proposed by Barzykin and Gor'kov we analyze the gap ratios on hole - like and electron - like Fermi - surface cylinders. It is shown that experimentally observed…
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…
Within a recently proposed variational approach it has been shown that, in $La_{1-x}A_xMnO_3$ perovskites with $0<x<0.5$, near the metal-insulator transition, the combined effect of the magnetic and electron-phonon interactions pushes the…
The transport and noise properties of Pr_{0.7}Ca_{0.3}MnO_{3} epitaxial thin films in the temperature range from room temperature to 160 K are reported. It is shown that both the broadband 1/f noise properties and the dependence of…
We have studied the terahertz response of a bulk single crystal of La$_{0.875}$Sr$_{0.125}$MnO$_3$ at around its Curie temperature, observing large changes in the real and imaginary parts of the optical conductivity as a function of…
Calculations of one-electron spectral functions, optical conductivity and spin-wave energy in the Holstein double-exchange model are made using the many-body coherent potential approximation. Satisfactory agreement is obtained with…
I present a selection of experimental results on metallic cuprates, both above the superconducting transition temperature $T_c$ (often called the strange metal state) and in the superconducting state. It highlights this still poorly…
The recent experimental observation of a metal-insulator transition in two dimensions prompts a re-examination of the theory of disordered interacting systems. We argue that the existing theory permits the existence of a metallic phase and…
The dielectric response of materials underpins electronics and photonics. Established semiconductor materials have a narrow range of dielectric susceptibility, with low-frequency values on the order of 10. Strong and variable dielectric…
Systems that can be described with the same mathematical models that account for the properties of electrons in graphene are known as graphene-like systems. These include magnons, photons, polaritons, acoustic waves, and electrons in…
We consider superconducting properties of a two-dimensional Dirac material such as graphene under strain that produces a flat band spectrum in the normal state. We show that in the superconducting state, such a model results in a highly…
The theory of thermodynamic properties of two-band superconductor with reduced density charge carriers is developed on the base of phonon superconducting mechanism with strong electron-phonon interaction. This theory is adapted to describe…
Existing experimental data for various colossal magnetoresistance manganites have been examined employing an ovesimplified model that roots in 1970th. This model considers a classical semiconductor where conducting bands are affected by the…