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FM: Fachverband Funktionsmaterialien

FM 12: German-French Focus Session: Materials Research in Polar Oxides – From Domain Engineering to Photonic and Electronic Devices I

FM 12.3: Vortrag

Mittwoch, 11. März 2026, 10:15–10:30, BEY/0138

Persistent photoconductivity in reduced lithium niobate bidomain crystals — •Philipp Fahler-Muenzer, Marios Hadjimichael, Ana Sanchez-Fuentes, Richard Beanland, Eoin Moynihan, and Marin Alexe — University of Warwick, Coventry, United Kingdom

The uniaxial ferroelectric lithium niobate (LiNbO3) can exhibit significantly enhanced domain wall (DW) conductivity, rendering it an interesting system for DW-based nanoelectronics. Specifically, head-to-head (h2h) DWs exhibit conductivities several orders of magnitude higher than that of the surrounding bulk. We create h2h DWs with a near-90^∘ inclination angle by using the diffusion annealing technique, followed by chemical treatment to change the functional properties. The characterization of the structure and morphology is conducted by piezoresponse force microscopy and transmission electron microscopy. To characterize electronic transport, we use resistivity measurements under varying temperatures in dark or under UV light illumination, complemented by conductive atomic force microscopy. Our findings indicate only transient conductivity at the DWs, but substantial differences in photoconductivity between monodomain and bidomain crystals, with persistent photoconductivity in crystals with DWs. Furthermore, we report a drastic drop in domain wall photoconductivity upon heating above 80^∘C, which can be explained by the emptying of charge carrier traps in the DW as the system gains higher thermal energy.

Keywords: lithium niobate; domain wall engineering; persistent photoconductivity; charge carrier trapping; atomic force microscopy