Effect of strain on charge density wave order in α-U
The effect of strain on charge density wave (CDW) order in $α$-U is investigated within the framework of relativistic density-functional theory. The energetical stability of $α$-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 $α$-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.