Effect of strain on charge density wave order in \alpha-U

TL;DR

This study uses relativistic density-functional theory to explore how strain affects charge density wave order in alpha-uranium, revealing directional dependencies that influence phase stability and electronic properties.

Contribution

It provides new insights into the directional effects of strain on CDW stability in alpha-uranium, linking atomic chain formation to electronic and phononic behavior.

Findings

Tensile strain along a and b enhances CDW stability.

Tensile strain along c suppresses CDW stability.

Strain effects are explained by changes in atomic chains and Fermi surface topology.

Abstract

The effect of strain on charge density wave (CDW) order in $\alpha$-U is investigated within the framework of relativistic density-functional theory. The energetical stability of $\alpha$-U with CDW distortion is enhanced by the tensile strain along $a$ and $b$ directions, which is similar to the case of negative pressure and normal. However, the tensile strain along $c$ direction suppresses the energetical stability of CDW phase. This abnormal effect could be understood from the emergence of a new one-dimensional atomic chain along $c$ direction in $\alpha$-U. Furthermore, this effect is supported by the calculations of Fermi surface and phonon mode, in which the topological objects and the dynamical instability show opposite behavior between strain along $a$/$b$ and $c$ directions.