Related papers: Acoustic Plasmons in MgB2
Recent first principles calculations of the phonon dispersion curves in MgB_2 have suggested the presence of anomalies in some of the curves, particularly in the longitudinal acoustical (LA) branch in the Gamma to A direction. Similar…
In a system consisting of two different charged species we identify the excitation of a second, low frequency plasmon. At strong coupling the doublet of high frequency (first) and low frequency (second) plasmons replaces the single plasmon…
Solid MgB$_2$ has rather interesting and technologically important properties, such as a very high superconducting transition temperature. Focusing on this compound, we report the first non-trivial application of a novel…
The frequency- and momentum-dependent dielectric function $\epsilon{(\bf q,\omega)}$ as well as the energy loss function Im[-$\epsilon^{-1}{(\bf q,\omega)}$\protect{]} are calculated for intermetallic superconductor $MgB_2$ by using two…
A sharp collective charge excitation is predicted in MgB$_2$ at $\sim2.5eV$ for $q$ perpendicular to the boron layers, based on an all-electron analysis of the dynamical density response within time-dependent density functional theory. This…
We show theoretically that the Coulomb drag rate between two parallel quasi-two-dimensional electron gases is substantially enhanced by the coupled acoustic and optic plasmon modes of the system at temperatures $T \gtrsim 0.2T_F$ (where…
A distinctive feature of layered conductors is the presence of low-energy electronic collective modes of the conduction electrons. This affects the dynamic screening properties of the Coulomb interaction in a layered material. We study the…
We report measurements of the superconducting critical temperature Tc of polycrystalline MgB2 samples containing isotopically pure (10)B and (11)B under quasi-hydrostatic pressure conditions in He pressure media up to 44 GPa. Measurements…
We characterize the superconducting state of phase pure polycrystalline samples of the new layered superconductor MgB$_2$ by specific heat measurements in magnetic fields up to 9 T. The characteristic jump at the superconducting transition…
We report inelastic neutron scattering measurements of the phonon density-of-states in Mg11B2, which has a superconducting transition at 39.2 K. The acoustic phonons extend in energy to 36 meV, and there are highly dispersive optic branches…
We examine the influence of collective excitations on the transport properties (resistivity, magneto- optical conductivity) for semimetals, focusing on the case of bismuth. We show, using an RPA approximation, that the properties of the…
Recently resonant inelastic x-ray scattering experiments reported fine details of the charge excitations around the in-plane momentum ${\bf q}_{\parallel}=(0,0)$ for various doping rates in electron-doped cuprates ${\rm La_{2-x}Ce_xCuO_4}$.…
We investigate the role of specific phonon mode symmetries for the room temperature superconductivity in atomic hydrogen under large pressure. Using anisotropic Migdal-Eliashberg theory with ab initio input from density functional theory,…
We show that a weak non-resonant tunneling between two quantum wires leads to splitting of the acoustic plasmon mode at finite wavevector. Two gaps open up in the dipersion of the acoustic plasmon mode when its frequency is close to the…
An acoustic plasmon is predicted to occur, in addition to the conventional two-dimensional (2D) plasmon, as the collective motion of a system of two types of electronic carriers coexisting in the very same 2D band of extrinsic (doped or…
The discovery of the first high critical temperature (Tc) transition metal diboride superconductor, MgB2 structure alpha-MoB2 under pressure with Tc up to 32 K at 100 GPa, provides new input into some unexplained aspects of electron-phonon…
The recent discovery of superconductivity at ~39 K in MgB2, by Nagamatsu et al. establishes this simple binary compound as having the highest bulk superconducting transition temperature, Tc, of any non-copper-oxide material. Much of the…
Pseudogap phase in superconductors continues to be an outstanding puzzle that differentiates unconventional superconductors from the conventional ones (BCS-superconductors). Employing high resolution photoemission spectroscopy on a highly…
The recently discovered superconductivity in MgB2 has captured world attention due to its simple crystal structure and relatively high superconducting transition temperature Tc=39K. It appears to be generally accepted that it is…
Plasmons, the collective excitations of electrons in the bulk or at the surface, play an important role in the properties of materials, and have generated the field of Plasmonics. We report the observation of a highly unusual acoustic…