Tunable spin polarization and superconductivity in engineered oxide interfaces

Nat Mater. 2016 Mar;15(3):278-83. doi: 10.1038/nmat4491. Epub 2015 Dec 7.

Abstract

Advances in growth technology of oxide materials allow single atomic layer control of heterostructures. In particular delta doping, a key materials' engineering tool in today's semiconductor technology, is now also available for oxides. Here we show that a fully electric-field-tunable spin-polarized and superconducting quasi-2D electron system (q2DES) can be artificially created by inserting a few unit cells of delta doping EuTiO3 at the interface between LaAlO3 and SrTiO3 oxides. Spin polarization emerges below the ferromagnetic transition temperature of the EuTiO3 layer (TFM = 6-8 K) and is due to the exchange interaction between the magnetic moments of Eu-4f and of Ti-3d electrons. Moreover, in a large region of the phase diagram, superconductivity sets in from a ferromagnetic normal state. The occurrence of magnetic interactions, superconductivity and spin-orbit coupling in the same q2DES makes the LaAlO3/EuTiO3/SrTiO3 system an intriguing platform for the emergence of novel quantum phases in low-dimensional materials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anisotropy
  • Magnetic Fields
  • Materials Testing
  • Metals / chemistry*
  • Oxides / chemistry*

Substances

  • Metals
  • Oxides