Soft-phonon-driven superconductivity in CaAlSi as seen by inelastic x-ray scattering

Abstract

Inelastic x-ray scattering and $ab$-$initio$ calculation are applied to investigate the lattice dynamics and electron-phonon coupling of the ternary silicide superconductor CaAlSi ($P/bar6m2$). A soft c-axis polarized mode is clearly observed along the $/Gamma$-$A$-$L$ symmetry directions. The soft mode is strongly anharmonically broadened at room temperature, but, at 10 K, its linewidth narrows and becomes in good agreement with calculations of linear electron-phonon coupling. This establishes a coherent description of the detailed phonon properties in this system and links them clearly and consistently with the superconductivity.

4 pages, 4 figures, to be published in Phys. Rev. B (Rapid Communications)

References in corpus (6)

• First-Principles Calculation of the Superconducting Transition in MgB2 within the Anisotropic Eliashberg Formalism
• Phonon dispersion and lifetimes in MgB2
• Kohn Anomaly in MgB2 by Inelastic X-Ray Scattering
• Electrons and phonons in the ternary alloy CaAl${}_{2-x}$Si${}_x$} as a function of composition
• Two-phonon contributions to inelastic x-ray scattering spectra of MgB2
• Electronic Structures of CaAlSi with Different Stacking AlSi Layers by First-Principles Calculations

Cited by in corpus (8)

• Superconductivity in the Honeycomb-Lattice Pnictide SrPtAs
• High-temperature superconductivity on the verge of a structural instability in lanthanum superhydride
• Multi-phonon diffuse scattering in solids from first-principles: Application to layered crystals and 2D materials
• Efficient first-principles methodology for the calculation of the all-phonon inelastic scattering in solids
• Enhancing the superconducting transition temperature of BaSi2 by structural tuning
• NaAlSi: a self-doped semimetallic superconductor with free electrons and covalent holes
• Anharmonic theory of superconductivity and its applications to emerging quantum materials
• Introduction to High-Resolution Inelastic X-Ray Scattering