Structural effect on the static spin and charge correlations in ${\mathrm{La}}_{1.875}{\mathrm{Ba}}_{0.125-x}{\mathrm{Sr}}_x{\mathrm{CuO}}_4$

We report the results of elastic neutron-scattering measurements performed on $\frac{1}{8}$-hole-doped ${\mathrm{La}}_{1.875}{\mathrm{Ba}}_{0.125-x}{\mathrm{Sr}}_x{\mathrm{CuO}}_4$ single crystals with $x=0.05,$ 0.06, 0.075, and 0.085. In the low-temperature less-orthorhombic [(LTLO), $\mathrm{Pccn}$ symmetry] phase, the charge-density-wave (CDW) and spin-density-wave (SDW) wave vectors were found to tilt in a low-symmetric direction with one-dimensional anisotropy in the ${\mathrm{CuO}}_2$ plane, while they were aligned along the high-symmetry axis in the low-temperature tetragonal ${(P4\mathrm{}}_2/ncm$ symmetry) phase. The coincident direction of two wave vectors suggests a close relation between CDW and SDW orders. The SDW wave vector systematically deviates from the Cu-O bond direction in the LTLO phase upon Sr substitution and the tilt angle in the LTLO phase is smaller than that in the low-temperature orthorhombic phase $(Bmab$ symmetry) with comparable in-plane orthorhombic distortion. These results demonstrate a correlation between the corrugated pattern of the ${\mathrm{CuO}}_2$ plane and the deviations.