Oxygen vacancies at titanate interfaces: two-dimensional magnetism and orbital reconstruction

Abstract

We show that oxygen vacancies at titanate interfaces induce a complex multiorbital reconstruction which involves a lowering of the local symmetry and an inversion of t2g and eg orbitals resulting in the occupation of the eg orbitals of Ti atoms neighboring the O vacancy. The orbital reconstruction depends strongly on the clustering of O vacancies and can be accompanied by a magnetic splitting between the local eg orbitals with lobes directed towards the vacancy and interface dxy orbitals. The reconstruction generates a two-dimensional interface magnetic state not observed in bulk SrTiO3. Using generalized gradient approximation (LSDA) with intra-atomic Coulomb repulsion (GGA+U), we find that this magnetic state is common for titanate surfaces and interfaces.

13 pages, 18 figures, to appear in Physical Review B

References in corpus (8)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Magnetic effects at the interface between nonmagnetic oxides
• High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Surface defects and conduction in polar oxide heterostructures
• Polarity-induced oxygen vacancies at LaAlO3|SrTiO3 interfaces
• Interface hole-doping in cuprate-titanate superlattices
• Mechanism of orbital reconstruction at the interfaces of transition metal oxides

Cited by in corpus (2)

• Ab initio study of the two-dimensional metallic state at the surface of SrTiO3: importance of oxygen vacancies
• Magnetically ordered state at correlated oxide interfaces: the role of random oxygen defects