Neutron scattering study of the kagome metal Sc3Mn3Al7Si5

TL;DR

This study uses neutron scattering to investigate phonon and magnetic excitations in the kagome metal Sc3Mn3Al7Si5, revealing dominant phonon behavior and weak magnetic fluctuations consistent with a frustrated, paramagnetic state.

Contribution

First inelastic neutron scattering analysis of Sc3Mn3Al7Si5, demonstrating phonon dominance and weak magnetic signals aligned with ab initio calculations and specific heat data.

Findings

Phonon scattering dominates at 20-50 meV.

Weak magnetic fluctuations observed below 10 meV.

Results agree with theoretical phonon models.

Abstract

Sc3Mn3Al7Si5 is a rare example of a correlated metal in which the Mn moments form a kagome lattice. The absence of magnetic ordering to the lowest temperatures suggests that geometrical frustration of magnetic interactions may lead to strong magnetic fluctuations. We have performed inelastic neutron scattering measurements on Sc3Mn3Al7Si5, finding that phonon scattering dominates for energies from ~20 - 50 meV. These results are in good agreement with ab initio calculations of the phonon dispersions and densities of states, and as well reproduce the measured specific heat. A weak magnetic signal was detected at energies less than ~10 meV, present only at the lowest temperatures. The magnetic signal is broad and quasielastic, as expected for metallic paramagnets.