Positive magnetoconductance in SrVO3 double quantum wells with a magnetic EuTiO3 barrier

Abstract

Controlling Mott insulator states has been a long-standing topic in condensed matter physics. Among various controlling parameters, two-dimensional (2D) confinement in epitaxial heterostructures has been demonstrated to convert the correlated metallic nature of SrVO3 into a Mott insulator by reducing the quantum well thickness. Here, we fabricate double quantum well (DQW) structures of SrVO3 with a magnetic barrier of EuTiO3 to tune the hybridization of wave functions by a magnetic field. A significant positive magnetoconductance is observed for DQWs with barriers thinner than 2 nm, while DQWs with thicker barriers do not show such large positive magnetoconductance, instead behaving as a parallel circuit of two single QWs. The observed positive magnetoconductance is accounted in terms of enhanced hybridization of V 3d orbitals across the EuTiO3 barrier under a magnetic field, where the barrier height is reduced by the Zeeman splitting of Ti 3d bands in forced ferromagnetic ordering of localized 4f electrons on Eu2+sites.