2,102 research outputs found
Density-functional calculations of the electronic structure and lattice dynamics of superconducting LaOFBiS: Evidence for an electron-phonon interaction near the charge-density-wave instability
We discuss the electronic structure, lattice dynamics and electron-phonon
interaction of newly discovered superconductor LaOFBiS
using density functional based calculations. A strong Fermi surface nesting at
=(,,0) suggests a proximity to charge density wave
instability and leads to imaginary harmonic phonons at this point
associated with in-plane displacements of S atoms. Total energy analysis
resolves only a shallow double-well potential well preventing the appearance of
static long-range order. Both harmonic and anharmonic contributions to
electron-phonon coupling are evaluated and give a total coupling constant
prompting this material to be a conventional
superconductor contrary to structurally similar FeAs materials.Comment: Supplementary Materials is adde
Analysis of the X(1576) as a tetraquark state with the QCD sum rules
In this letter, we take the point of view that the X(1576) be tetraquark
state which consists of a scalar-diquark and an anti-scalar-diquark in relative
-wave, and calculate its mass in the framework of the QCD sum rules
approach. The numerical value of the mass is
consistent with the experimental data, there may be some tetraquark component
in the vector meson X(1576).Comment: 6 pages, 1 figure, second version, typos correcte
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