Superconductivity near the vibrational-mode instability inMgCNi3

Superconductivity near ferromagnetism in MgCNi3.

An unusual quasi-two-dimensional heavy band mass van Hove singularity (vHs) lies very near the Fermi energy in MgCNi3, recently reported to superconduct at 8.5 K. This compound is strongly exchange enhanced and unstable to ferromagnetism upon hole doping with approximately 12% Mg-->Na or Li (i.e., 0.04 hole/Ni). We identify an essentially infinite mass along the M-Gamma line, which accounts for...

Doping-dependent Phase Diagram of LaOMAs (M=V–Cu) and Electron-type Superconductivity near Ferromagnetic Instability

By first-principles calculations, we present a doping-dependent phase diagram of LaOMAs (M=V–Cu) family. It is characterized as antiferromagnetic semiconductor around LaOMnAs side and ferromagnetic metal around LaOCoAs. Both LaOFeAs and LaONiAs, where superconductivity were discovered, are located at the borderline of magnetic phases. Extensive Fermi surface analysis suggests that the observed ...

Structural instability and superconductivity in Ba1−xKxBiO3

We report results of the ultrasonic investigation of Ba1−xKxBiO3 superconducting (SC) single crystals for two potassium concentrations x ∼= 0.35 and x ∼= 0.47 in a wide temperature range including the normal and the SC states. An instability of the crystal lattice that develops above the superconducting phase transition leads to a softening of both the transverse c44 and the longitudinal c11 mo...

Title Gossamer superconductivity near antiferromagnetic mott

Gravitational radiation from the r-mode instability

The instability in the r-modes of rotating neutron stars can (in principle) emit substantial amounts of gravitational radiation (GR) which might be detectable by LIGO and similar detectors. Estimates are given here of the detectability of this GR based the non-linear simulations of the r-mode instability by Lindblom, Tohline and Vallisneri. The burst of GR produced by the instability in the rap...