Lattice dynamical properties of superconducting SrPt${}_3$P studied via inelastic x-ray scattering and density functional perturbation theory

Abstract

We present a study of the lattice dynamical properties of superconducting SrPt${}_3$P ($T_c=8.4$ K) via high-resolution inelastic x-ray scattering (IXS) and ab initio calculations. Density functional perturbation theory including spin-orbit coupling (SOC) results in enhanced electron-phonon coupling (EPC) for the optic phonon modes originating from the Pt(I) atoms, with energies $\sim 5$ meV, resulting in a large EPC constant $\lambda \sim 2$. An overall softening of the IXS powder spectra occurs from room to low temperatures, consistent with the predicted strong EPC and with recent specific-heat experiments ($2{\Delta }_0/k_{\mathrm{B}}{T}_c\sim 5$). The low-lying phonon modes observed in the experiments are approximately 1.5 meV harder than the corresponding calculated phonon branch. Moreover, we do not find any changes in the spectra upon entering the superconducting phase. We conclude that current theoretical calculations underestimate the energy of the lowest band of phonon modes indicating that the coupling of these modes to the electronic subsystem is overestimated.

5 pages, 3 figures

References in corpus (5)

• Conventional superconductivity at 203 K at high pressures
• Electronic and vibrational properties of ${\text{TiSe}}_2$ in the charge-density wave phase from first principles
• SrPt${}_3$P: two-band single-gap superconductor
• Phonons and electron-phonon coupling in the phonon-mediated superconductor YNi2B2C
• Electron and phonon band-structure calculations for the antipolar SrPt${}_3$P antiperovskite superconductor: Evidence of low-energy two-dimensional phonons

Cited by in corpus (8)

• Symmorphic and nonsymmorphic symmetries jointly-protected hourglass phonons
• Superconductivity and hybrid soft modes in TiSe${}_2$
• Exact factorization-based density functional theory of electron-phonon systems
• High pressure crystal growth of the antiperovskite centrosymmetric superconductor SrPt3P
• The effects of electron correlation and spin-orbit coupling in the isovalent Pd-doped superconductor SrPt${}_3$P
• Introduction to High-Resolution Inelastic X-Ray Scattering
• Antiferromagnetic Kondo lattice compound CePt${}_3$P
• Possible unconventional order parameter in single crystals of SrPt${}_3$P superconductor