The enigmatic mechanism underlying unconventional high-temperature
superconductivity, especially the role of lattice dynamics, has remained a
subject of debate. Theoretical insights have long been hindered due to the lack
of an accurate first-principles description of the lattice dynamics of
cuprates. Recently, using the r2SCAN meta-GGA functional, we were able to
achieve accurate phonon spectra of an insulating cuprate YBa2โCu3โO6โ,
and discover significant magnetoelastic coupling in experimentally interesting
Cu-O bond stretching optical modes [Phys. Rev. B 107, 045126 (2023)]. We extend
this work by comparing PBE and r2SCAN performances with corrections from the
on-site Hubbard U and the D4 van der Waals (vdW) methods, aiming at further
understanding on both the materials science side and the density functional
side. We demonstrate the importance of vdW and self-interaction corrections for
accurate first-principles YBa2 Cu3 O6 lattice dynamics. Since r2SCAN by itself
partially accounts for these effects, the good performance of r2SCAN is now
more fully explained. In addition, the performances of the Tao-Mo series of
meta-GGAs, which are constructed in a different way from SCAN/r2SCAN, are also
compared and discussed.Comment: arXiv admin note: text overlap with arXiv:2210.0656