The two-dimensional electron system in (110)Al2O3−δ/SrTiO3 heterostructures displays anisotropic electronic transport. Largest and lowest conductivity and electron mobility μ are observed along the [001] and [11ˉ0] direction, respectively. The anisotropy of the sheet resistance and μ likewise leads to a distinct anisotropic normal magnetotransport (MR) for T < 30K. However, at temperatures T<5K and magnetic field B<2T MR is dominated by weak antilocalization.Despite the rather strong anisotropy of the Fermi surfaces, the in-plane anisotropic magnetoresistance (AMR) displays two-fold non-crystalline anisotropy. However, the AMR-amplitude is found to be anisotropic with respect to the current direction, leading to a 60% larger AMR amplitude for current I along the [001] direction compared to I parallel to [11ˉ0]. Tight binding calulations evidence an anisotropic Rashba-induced band splitting with dominant linear k-dependence. In combination with semiclassical Boltzmann theory the non-crystalline AMR is well described, despite the anisotropic Fermi surface.
@article{arxiv.1803.02646,
title = {Anisotropic electronic transport and Rashba effect of the two-dimensional electron system in (110) SrTiO$_3$-based heterostructures},
author = {K. Wolff and R. Eder and R. Schäfer and R. Schneider and D. Fuchs},
journal= {arXiv preprint arXiv:1803.02646},
year = {2018}
}