Related papers: Anomalous electron-phonon interaction in doped LaO…
The coupling of Fe magnetic moments in LaFeAsO$_{1-x}$F$_{x}$ with the As $A_{1g}$ phonon is calculated. We present first principles calculations of the atomic and electronic structure of LaFeAsO as a function of electron doping. We perform…
When either electron or hole doped at concentrations $x\sim 0.1$, the LaOFeAs family displays remarkably high temperature superconductivity with T$_c$ up to 55 K. In the most energetically stable $\vec Q_M = (\pi,\pi)$ antiferromagnetic…
From first principles calculations we find that the nearest and next nearest neighbor superexchange interactions between Fe ions in LaOFeAs are large, antiferromagnetic (AF), and give rise to a frustrated magnetic ground state which…
We measured phonon frequencies and linewidths in doped and undoped BaFe2As2 single crystals by inelastic x-ray scattering and compared our results with density functional theory (DFT) calculations. In agreement with previous work, the…
From first-principles calculations, we have studied the electronic and magnetic structures of the ground state of LaOFeAs. The Fe spins are found to be collinear antiferromagnetic ordered, resulting from the interplay between the strong…
Magnetic and electronic structures in LaFeAsO in the single-stripe-type antiferromagnetic (AFM) phase are studied using first-principles density-functional calculations including the spin-orbit interaction. We show that the longitudinal…
Structural, electronic, and magnetic properties of undoped and aliovalent-ion (Ca, F)-doped LaOFeP, which undergo superconducting transitions at transition temperatures (Tc) 4-7 K [Kamihara et al, J. Am. Chem. Soc. 128, 10012, (2006)], were…
The interplay of the electron-phonon interaction and of the double and super exchange magnetic effects is analyzed in the $La_{1-x}Ca_xMnO_3$ perovskites with $0<x<0.5$. By using an analytical variational scheme that allows to treat the…
Although plasmons and phonons are the collective excitations that govern the low-energy physics of doped semiconductors, their nonadiabatic hybridization and mutual screening have not been studied from first principles. We achieve this goal…
Systems with strong electron-phonon couplings typically exhibit various forms of charge order, while strong electron-electron interactions lead to magnetism. We use determinant quantum Monte Carlo (DQMC) calculations to solve a model on a…
In contrast to hole-doped systems which have hole pockets centered at $(\pm \frac{\pi}{2a},\pm \frac{\pi}{2a})$, in lightly electron-doped antiferromagnets the charged quasiparticles reside in momentum space pockets centered at…
The electron-phonon coupling of LaO$_{1-x}$F$_x$FeAs is re-investigated on the basis of density functional theory in local density approximation. The implications of the $(\pi,\pi)$ nesting of the Fermi surfaces are carefully studied and…
Describing electron-phonon interactions in a solid requires knowledge of the electron-phonon matrix elements in the Hamiltonian. State-of-the-art first-principles calculations for the electron-phonon interaction are limited to the…
FeGa$_3$ is an unusual intermetallic semiconductor that presents intriguing magnetic responses to the tuning of its electronic properties. When doped with Ge, the system evolves from diamagnetic to paramagnetic to ferromagnetic ground…
Using a multistep renormalization group method, we study the low-temperature phases of the interacting one-dimensional (1D) electron gas coupled to phonons. We obtain analytic expressions for the weak-coupling quantum phase boundaries of…
Electron-phonon interactions in solids are crucial for understanding many interesting phenomena, such as conventional superconductivity, temperature-dependent band-gap renormalization, and polarons. For harmonic materials, the linear…
A detailed investigation of mesoscopic magnetic and crystallographic phase separation in Ca(1-x)La(x)MnO3, 0.00<=x<=0.20, is reported. Neutron powder diffraction and DC-magnetization techniques have been used to isolate the different roles…
The possibility of superconducting pairing of electrons in doped graphene due to in-plane and out-of-plane phonons is studied. Quadratic coupling of electrons with out-of-plane phonons is considered in details, taking into account both…
Multiferroics possess two or more switchable states such as polarization, magnetization, etc. Phonon excitations in multiferroic phase are strongly modified by magnetoelectric coupling, spin-phonon coupling, and anharmonic phonon-phonon…
We develop a unified treatment of the piesoelectric coupling between two-dimensional electrons and bulk phonons in both cases of zero and strong magnetic fields, the latter corresponding to even denominator filling fractions. In contrast to…