Recent important progresses in the filed of HTSCs
Stripe formation is a good way to interpret the coexistence of antiferromagnetism order and superconductivity in HTSCs. However, the spectrum of magnetic excitation of YBCO is not consistent with the theoretical prediction for a material including stripes. A group of scientists from the USA, UK, and Japan have investigated this contraction by measuring inelastic neutron [...]
In an electron-phonon system the electron-phonon interaction spectral density, α2F(ω), is approximately equal to W(ω) defined as:
α2F(ω)≈W(ω)=(1/2π)d2[ωRe(σ-1(ω))]/dω2 (1)
Where, Re(σ(ω)) is the real part of the optical conductivity. For the electron-spin interaction systems this relation could be converted to I2χ(ω)≈W(ω), where I is the coupling constant of electron-spin interaction and χ(ω) is the imaginary part [...]
The most prominent feature of spin fluctuation in YBCO6+x system is the 41 meV resonance peak which appears below the Tc of the optimal sample. This feature (and strong spin fluctuation for all x values in this system) has been considered as an important experimental evidence for the magnetic interaction pairing of HTSCs although its [...]
Dramatic changes in the magnetic excitation spectrum by going to the superconducting state of HTSCs, known as the “resonance” peak, have been considered as a strong evidence for the magnetic pairing mechanism of superconductivity in these systems. The resonance peak occurs at Eres=41 and 34 meV [at q=(0.5, 0.5) in the CuO2 reciprocal lattice units [...]
A group of scientists from Germany, France, Japan, and United States has recently reported some experimental evidences that relate the phonon softening of oxygen bond-stretching vibration mode in HTSCs to the stripe order. The basic idea of this study is that charge inhomogeneity with a periodic modulation (for example stripes) should affect interatomic Coulomb forces [...]
