Resonant transport assisted by a charged domain wall in a ferroelectric tunnel junction

Interfacially induced electronic states at oxide interfaces can be used to tailor novel functionalities. In this talk we discuss the possibility to exploit the unavoidable defects at interfaces to tailor novel electronic states. In particular, oxygen vacancies, difficult to detect and in many cases also to avoid in oxides heterostructures, may have drastic effects on materials properties. Under the strong electric fields developing in nanostructures at moderate voltages, oxygen vacancies may accumulate at interfaces and drastically alter their physical properties through their associated strain and doping fields. Here we will describe the controlled and manipulation of the oxygen vacancy profile in a ferroelectric tunnel barrier, showing that oxygen vacancies may stabilize unexpected domain structures. We describe the nucleation of a charged domain wall in a ferroelectric nanometer thick tunnel barrier, and how it controls transport by a resonant tunneling mechanism assisted by the highly confined screening electronic states [1]. This result provides a major step forward towards the concept “The Wall is the Device”, to exploit the electronic properties of domain walls for ferroelectric tunnel barriers with new functionalities.

[1] G. Sanchez Santolino, J. Tornos et al. Nature Nanotechnology 12, 655 (2017)

Work done in collaboration with J. Tornos¹, G. Sanchez-Santolino², D. Hernandez-Martin¹, F. Gallego¹, G. Orfila ¹, M. Cabero¹, A. Perez-Muñoz¹ M. Varela², J. I. Beltran³, C. Munuera³, A. Rivera-Calzada¹, Z. Sefrioui¹, F. Mompean³, S. J. Pennycook⁴, M. C. Muñoz³, M. Garcia-Hernandez², C. Leon<sup>1

1</sup> GFMC, Universidad Complutense de Madrid, 28040 Madrid, Spain AND Unidad Asociada ICMM-CSIC "Laboratorio de heteroestructuras con aplicación en Espintrónica"
² Universidad Complutense de Madrid, 28040 Madrid, Spain.
³ Instituto de Ciencia de Materiales de Madrid ICMM-CSIC
⁴ Department of Mat. Sci.& Engineering, Natnl. University of Singapore, Singapore 117575