Talk by William Meier

A Catastrophic charge density wave in BaFe₂Al₉

Abstract

Interest in the physics and the origins of charge density waves (CDWs) has experienced a renaissance in the last years driven by excitement around kagome metals.

Although the prototypical materials that host these combined structural and electronic modulations possess low dimensional chains or sheets, a remarkable number of 3D intermetallic compounds stand apart. BaFe₂Al₉ is an unusual example of such a compound that develops CDW order below 100K. On cooling through the first order transition, an incommensurate modulation develops accompanied by a significant change in lattice size.

This strain has a remarkable consequence for the crystals, and they physically shatter. Electronic structure calculation, chemical substitutions, and comparisons with the less dramatic cobalt version, BaCo₂Al₉, suggest that the iron d-orbital states and lattice energy costs play important roles in CDW formation.

Host

Morten Holm Christensen