The electronic and phonon properties of the platinum pnictide superconductors APt3P (A=Ca, Sr, and La) were studied using first-principles calculations. The spin-orbit coupling effect is significant in LaPt3P but negligible in CaPt3P and SrPt3P, although they all share the same anti-pevroskite structure. Moreover, SrPt3P has been demonstrated to exhibit an unexpected weak charge-density-wave(CDW) instability which is neither simply related to the Fermi-surface nesting nor to the momentum-dependent electron-phonon coupling alone. The instability is absent in CaPt3P and can be quickly suppressed by the external pressure, accompanied with gradual decreases in the phonon softening and BCS Tc. Our results suggest SrPt3P as a rare example where superconductivity is enhanced by the CDW fluctuations.
@article{arxiv.1206.4147,
title = {Charge Density Wave Instability and Soft Phonon in $A$Pt$_3$P ($A$=Ca, Sr, and La)},
author = {Hui Chen and Xiaofeng Xu and Chao Cao and Jianhui Dai},
journal= {arXiv preprint arXiv:1206.4147},
year = {2013}
}