Program Highlights

Ferroelectric Domain Wall as a Memristor

Alexei Gruverman, Alexander Sinitskii, and Jeffrey Shield
Nebraska MRSEC

Marty Gregg
Queen's University Belfast 

Ferroelectric materials consist of domains that are spontaneously polarized along the directions allowed by symmetry. Domain walls are boundaries between the domains, where the polarization orientation changes abruptly. Ferroelectric domain walls have recently aroused significant scientific interest due to their electrical conductivity that may be used in future nanoelectronics.
Nebraska MRSEC researchers in collaboration with their colleagues at Queen's University Belfast have discovered the electrical modulation of domain-wall conductivity in ferroelectric lithium niobate thin films down to the nanoscale. They showed that the domain-wall conductivity strongly depends on the preset voltage pulse polarity, amplitude, and duration, giving rise to multilevel conducting states that depend on the history of the pulses applied to the domain wall. Such a behavior is intrinsic to a memristor – a novel, not yet employed logic element. Memristors are important because they are non-volatile, i.e. retain memory without power, and have multiple resistance states. These results open a new functionality of a ferroelectric domain wall which may serve as a memristor in future nanoelectronics.

This research is supported by the National Science Foundation, Division of Materials Research, Materials Research Science and Engineering Program, Grant DMR-1420645.

Electrical control of domain wall conductivity in lithium niobate thin films: (left panel) images of two domains and a domain wall between them; (right panel) a color map showing local domain-wall conductivity for different voltage pulses. It is seen that the local conductivity along the domain wall changes depending on magnitude and duration of the voltage pulse.