Open AccessFirst-principles study on phonon properties of iron-based fluoride superconductors SrFe1-xCoxAsF (x=0, 0.125)
Author(s) -
Wei Wang,
Xi Yin
Publication year - 2014
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.63.097401
Subject(s) - condensed matter physics , pseudopotential , phonon , superconductivity , tetragonal crystal system , coupling (piping) , materials science , orthorhombic crystal system , antiferromagnetism , pairing , physics , diffraction , phase (matter) , quantum mechanics , metallurgy
Using plane-wave pseudopotential method based on first-principles, we calculate the phonon spectra (including phonon dispersion curves and phonon density of states) and electron-phonon coupling constants of SrFe1-xCoxAsF (x=0, 0.125) in tetragonal nonmagnetic (NM) and orthorhombic striped antiferromagnetic (SAF) states. Results show that under striped antiferromagetic interaction the spin-phonon coupling is stronger than the electron-phonon coupling, leading to the decrease of phonon spectra width; and the increased effective phonon quality due to spin effects makes the frequencies of coupling vibration between Fe and As atoms reduced. In addition, doping and spin effects are two effective methods to enhance the electron-phonon coupling, however, the calculated superconducting transition temperature is far lower than the experimental measurement, which rules out the simple electron-coupling superconducting pairing mechanism in SrFe1-xCoxAsF.