The Effect of Biaxial Strain and Layer Thickness on Octahedral Rotation in LaNiO$_3$

Heterostructures of complex oxides have attracted great attention for the interplay between structure, electronic, and magnetic properties, offering unique opportunities in device applications. Here we investigate the effects of epitaxial strain and layer thickness on the structural properties of LaNiO$_3$. We perform first-principles calculations based on density functional theory to investigate the NiO$_6$ octahedral tilts and Ni-O bond lengths of biaxially stressed LaNiO$_3$ layers in LaNiO$_3$/SrTiO$_3$ superlattices. Recent experimental results suggest that octahedral connectivity in these superlattices strongly influence the octahedral rotations in the LaNiO$_3$ layer, and thus, determines its electronic behavior. In this talk we will present a quantitative analysis for the octahedral tilt angles as a function of both biaxial stress and distance from the substrate for LaNiO$_3$ grown on SrTiO$_3$ (001). Our results indicate that LaNiO$_3$ exhibits vanishing octahedral tilt angles under certain strain conditions, a finding that holds important consequences for its electronic properties.