We have carried out a systematic study of the tilted magnetic field induced anisotropy at the Landau level filling factor $\nu =5/2$ in a series of high quality GaAs quantum wells, where the setback distance ($d$) between the modulation doping layer and the GaAs quantum well is varied from 33 to 164 nm. We have observed that in the sample of the smallest $d$, electronic transport is anisotropic when the in-plane magnetic field ($B_{\mathrm{ip}}$) is parallel to the $[1–10]$ crystallographic direction, but remains more or less isotropic when $B_{\mathrm{ip}}\parallel \left[110\right]$. In contrast, in the sample of largest $d$, electronic transport is anisotropic in both crystallographic directions. Our results clearly show that the modulation doping layer plays an important role in the tilted field induced $\nu =5/2$ anisotropy.

• Received 20 December 2014
• Revised 13 March 2015

DOI:https://doi.org/10.1103/PhysRevB.91.125308