Magnetoresistance in the superconducting state at the (111) LaAlO${}_3$/SrTiO${}_3$ interface

Abstract

Condensed matter systems that simultaneously exhibit superconductivity and ferromagnetism are rare due the antagonistic relationship between conventional spin-singlet superconductivity and ferromagnetic order. In materials in which superconductivity and magnetic order is known to coexist (such as some heavy-fermion materials), the superconductivity is thought to be of an unconventional nature. Recently, the conducting gas that lives at the interface between the perovskite band insulators LaAlO${}_3$ (LAO) and SrTiO${}_3$ (STO) has also been shown to host both superconductivity and magnetism. Most previous research has focused on LAO/STO samples in which the interface is in the (001) crystal plane. Relatively little work has focused on the (111) crystal orientation, which has hexagonal symmetry at the interface, and has been predicted to have potentially interesting topological properties, including unconventional superconducting pairing states. Here we report measurements of the magnetoresistance of (111) LAO/STO heterostructures at temperatures at which they are also superconducting. As with the (001) structures, the magnetoresistance is hysteretic, indicating the coexistence of magnetism and superconductivity, but in addition, we find that this magnetoresistance is anisotropic. Such an anisotropic response is completely unexpected in the superconducting state, and suggests that (111) LAO/STO heterostructures may support unconventional superconductivity.

arXiv comment6 Pages 4 figures

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Cited by in corpus (13)

• Discovery of two-dimensional anisotropic superconductivity at KTaO${}_3$ (111) interfaces
• Two-dimensional superconductivity at the surfaces of KTaO3 gated with ionic liquid
• Band inversion driven by electronic correlations at the (111) LaAlO${}_3$/SrTiO${}_3$ interface
• Tunable spin and orbital Edelstein effect at (111) LaAlO${}_3$/SrTiO${}_3$ interface
• Gate tunable anomalous Hall effect: a Berry curvature probe at oxides interfaces
• Superconductivity and Frozen Electronic States at the (111) LaAlO${}_3$/SrTiO${}_3$ Interface
• Strain-induced topological phase transition at (111) SrTiO${}_3$-based heterostructures
• Signatures of Electronic Nematicity in (111) LaAlO${}_3$/SrTiO${}_3$ Interfaces
• Vortex excitations in the Insulating State of an Oxide Interface
• Low temperature magnetoresistance of (111) (La${}_{0.3}$Sr${}_{0.7}$)(Al${}_{0.65}$Ta${}_{0.35}$)/SrTiO${}_3$
• Strong spin-orbit coupling and magnetism in (111) (La${}_{0.3}$Sr${}_{0.7}$)(Al${}_{0.65}$Ta${}_{0.35})$/SrTiO${}_3$
• Fluctuations superconductivity and giant negative magnetoresistance in a gate voltage tuned 2D electron liquid with strong spin-orbit impurity scattering
• Absence of localized $5d^1$ electrons in KTaO${}_3$ interface superconductors