Electrostatic force microscopy reveals abruptly changing and geometrically confined electron conductance in SrMnO3 thin films grown on a (La,Sr)(Al,Ta)O3 substrate. Using density functional theory calculations, this effect is explained to originate from tensile strain-induced oxygen vacancies that preferentially accumulate at ferroelectric domain walls, where they induce a 24 meV potential barrier that prevents electron conduction below 400K.
The regions bordered by these vacancy-decorated domain walls can be individually charged and retain their charge for hours, opening potential applications for example in data storage.
This work was carried out in the group of Prof. Ulrich Aschauer in collaboration with Prof. Manfred Fiebig (ETHZ), Prof. Nicola Spaldin (ETHZ), and Prof. José Pardo (Zaragoza).
C. Becher, L. Maurel, U. Aschauer, M. Lilienblum, C. Magén, D. Meier, E. Langenberg, M. Trassin, J. Blasco, I. P. Krug, P. A. Algarabel, N. A. Spaldin, J. A. Pardo, M. Fiebig;
"Strain-induced coupling of electrical polarization and structural defects in SrMnO3 films"
Nature Nanotechnol., 2015, 10(8), 661-665;