Weak antilocalization within a genuine multiband model

Abstract

Weak antilocalization signatures in magnetotransport measurements provide specific information about the spin-orbit coupling at oxide interfaces. However, for many of these two-dimensional systems, the commonly used theory for single-band electrons is not appropriate. The atomic spin-orbit coupling, jointly with inversion symmetry breaking terms, mixes states of different bands, making a multiband treatment of the Cooperon equation unavoidable. Here we consider an effective ${t}_{2g}$ multiband model that allows a decomposition into a pseudospin representation $1/2\phantom{\rule{0.16em}{0ex}}\ensuremath{\bigoplus}\phantom{\rule{0.16em}{0ex}}3/2$. For the spin-$3/2$ sector, supervening quintet and septet channels from the Cooperon $3/2\phantom{\rule{0.16em}{0ex}}\ensuremath{\bigotimes}\phantom{\rule{0.16em}{0ex}}3/2$ representations alter the quantum correction considerably. We study the impact of the spin winding number at the Fermi surface and report about a new experimentally accessible structure in the magnetoconductivity that is sensitive to the ratio of single and triple spin winding contributions.