Related papers: Ferroelectricity in (K@C$_{60}$)$_n$
The influence of depolarizing field on the magnitude and stability of a uniform polarization in ferroelectric capacitors and tunnel junctions is studied using a nonlinear thermodynamic theory. It is predicted that, in heterostructures…
Mysterious high temperature structureless transitions in (TMTTF)2X compounds have been discovered in mid 80's (Coulon, Lawersanne,vet al), but left unexplained and abandoned, together with other warnings from structural effects (Moret,…
We construct a mean-field theory for itinerant ferromagnetism coexisting with a non-unitary superconducting state, where only the majority-spin band is gapped and contains line nodes, while the minority-spin band is gapless at the Fermi…
We discuss ferroelectric phase transitions into single- and multidomain states in very thin films using continuous theory. It is shown that in nearly cubic ferroelectrics the domain state may survive down to atomic film thicknesses, unlike…
We analyze a system of polar molecules in a one-dimensional optical lattice. By controlling the internal structure of the polar molecules with static electric and microwave fields, we demonstrate the appearance of a quantum phase transition…
In this work we investigate the ground state of a momentum-confined interacting 2D electron gas, a momentum-space analog of an infinite quantum well. The study is performed by combining analytical results with a numerical exact…
The two-orbital model for manganites with both non-cooperative and cooperative Jahn-Teller phonons is studied at hole density x=0.5 using Monte Carlo techniques. The phase diagram is obtained varying the electron-phonon coupling and the…
Ground-state structure is found and pressure-induced phase transitions up to 210 kbar are studied in mercury titanate from first principles within the density functional theory. It is established that the $R3c$ structure experimentally…
The electronic and structural properties of Li$B$O$_3$ ($B$=V, Nb, Ta, Os) are investigated via first-principles methods. We show that Li$B$O$_3$ belong to the recently proposed hyperferroelectrics, i.e., they all have unstable longitudinal…
The extrapolation of small-cluster exact-diagonalization calculations is used to examine ferromagnetism in the one-dimensional Hubbard model with a generalized type of hopping. It is found that the long-range hopping with power decaying…
We study the ground state properties of the Holstein-Hubbard model on some bipartite lattices at half-filling; The ground state is proved to exhibit ferrimagnetism whenever the electron-phonon interaction is not so strong. In addition, the…
We explore various temperature dependencies and thermodynamic quantities of a mean field model of a ferromagnetic-superconducting system. The starting point for this model is based on an s-wave pairing scheme in the singlet channel of the…
The ground states of electrons in two vertically coupled quantum dots in the presence of an external magnetic field have been studied within the density functional theory. A phase diagram of the transition to the quantum Hall state in…
Due to the frequent presence of a Berry phase, in most cases of dynamical Jahn-Teller systems the symmetry of the ground state is the same as that of the electronic state. However, the H x h icosahedral case, relevant for the physics of…
A model for the coexistence of p-wave superconductivity (SC) and ferroelectricity (FE) is presented. The Hamiltonian of SC sector and FE sector can be diagonalized by using the $so(5)$ and $h(4)$ algebraic coherent states respectively. We…
We consider a state-of-the-art ferroelectric phase-field model arising from the engineering area in recent years, which is mathematically formulated as a coupled elliptic-parabolic differential system. We utilize a fixed point theorem based…
The benzene cation (C6H6+) has a doublet (e_{1g}) ground state in hexagonal ring (D_{6h}) geometry. Therefore a Jahn-Teller (JT) distortion will lower the energy. The present theoretical study yields a model Huckel-type Hamiltonian that…
Observation of ferroelectricity among non-d0 systems, which was believed for a long time an unrealistic concept, led to various proposals for the mechanisms to explain the same (i.e. magnetically induced ferroelectricity) during last…
In the present work ferromagnetic ordering in the Hubbard model generalized by taking into account the inter-atomic exchange interaction and correlated hopping in partially filled narrow band is considered. In the case of weak…
We explore the effect of charge carrier doping on ferroelectricity using density functional calculations and phenomenological modeling. By considering a prototypical ferroelectric material, BaTiO3, we demonstrate that ferroelectric…