Polarization Control of Electron Tunneling into Ferroelectric Surfaces

• Published in: Science (American Association for the Advancement of Science) Vol. 324; no. 5933; pp. 1421 - 1425
• Main Authors: Maksymovych, Peter, Jesse, Stephen, Yu, Pu, Ramesh, Ramamoorthy, Baddorf, Arthur P, Kalinin, Sergei V
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 12.06.2009; The American Association for the Advancement of Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Data storage; Dielectric thin films; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electric current; electric field; Electric fields; electron transfer; Electron tunneling; Electrons; Exact sciences and technology; Ferroelectricity and antiferroelectricity; Hysteresis; lead; Material films; Materials science; Oxides; ozone; Physics; Piezoelectricity and electromechanical effects; Polarization; Quantum tunneling; Switching phenomena; Thin films; Atomic force microscopy; Tunnel effect; PZT; Electric field effects; High field; Electron mobility; Piezoelectricity; Ferroelectric switching; Spontaneous polarization; Ferroelectric thin films; Fowler Nordheim tunneling; Spintronics; Charge carrier injection
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1171200

We demonstrate a highly reproducible control of local electron transport through a ferroelectric oxide via its spontaneous polarization. Electrons are injected from the tip of an atomic force microscope into a thin film of lead-zirconate titanate, Pb(Zr₀.₂Ti₀.₈)O₃, in the regime of electron tunneling assisted by a high electric field (Fowler-Nordheim tunneling). The tunneling current exhibits a pronounced hysteresis with abrupt switching events that coincide, within experimental resolution, with the local switching of ferroelectric polarization. The large spontaneous polarization of the PZT film results in up to 500-fold amplification of the tunneling current upon ferroelectric switching. The magnitude of the effect is subject to electrostatic control via ferroelectric switching, suggesting possible applications in ultrahigh-density data storage and spintronics.