Anisotropic magnetoresistance and planar Hall effect in (001) and (111) LaVO3/SrTiO3 heterostructures

A two-dimensional electron gas at the interfaces of perovskite oxides has unfolded various emergent phenomena. In this work, we fabricate the conducting interface between LaVO3 (LVO) and SrTiO3 (STO) with two different orientations, (001) and (111), employing a pulsed laser deposition system. A signature of weak antilocalization is observed in the (111)-oriented LVO/STO heterostructure which was not present in the (001) heterostructure. We report the observation of a planar Hall effect (PHE) and anisotropic magnetoresistance (AMR) for both heterointerfaces. The AMR and PHE are measured by driving a current I in the plane of the interface and applying an external magnetic field B in the same plane. The angular dependence (angle phi between B and I) of AMR and PHE in both cases is observed to be sensitive to applied magnetic field and temperature. The (001)-oriented heterointerface shows larger AMR (similar to 60%) than (111) (<10%), which is the highest among previously reported oxide heterostructures. The PHE shows twofold symmetry as a function of phi for both interfaces, and the symmetry remains for all the magnetic field values. In contrast, the AMRs for (001) and (111) have different symmetries. At the same time, they have strong dependence on B. A detailed analysis of our results and density functional theory calculations suggests that the origin of these oscillations (AMR and PHE) observed in (001)- and (111)-oriented LVO/STO interfaces can be linked to their unique Fermi surface reconstruction due to its orbital occupancy and polarization/hybridization.

Automated summary

A two-dimensional electron gas at the interfaces of perovskite oxides has exhibited various emergent phenomena, including weak antilocalization, planar Hall effect, and anisotropic magnetoresistance. The (001)-oriented heterointerface shows a higher anisotropic magnetoresistance compared to the (111)-oriented heterointerface, with unique characteristics observed for both orientations. These phenomena can be linked to Fermi surface reconstruction due to orbital occupancy and polarization/hybridization.