Polar discontinuities, emergent conductivity, and critical twist-angle-dependent behaviour at wafer-bonded ferroelectric interfaces
Abstract
Abstract Probing novel properties, arising from twisted interfaces, has traditionally relied on the stacking of exfoliated two-dimensional materials and the spontaneous formation of van der Waals bonds. So far, investigations involving intimate covalent or ionic bonds have not been a focus. Yet, we show here that an established technique, involving thermocompressional wafer bonding, works well for creating twisted non-van der Waals interfaces. We have successfully bonded z-cut lithium niobate single crystals to create ferroelectric oxide interfaces with strong polar discontinuities and have mapped the associated emergent interfacial conductivity. In some instances, a dramatic change in microstructure occurs, involving local dipolar switching. A twist-induced collapse in the capability of the system to effec8tively screen interfacial bound charge is implied. Importantly, this only occurs around specific moiré twist angles with sparse coincident lattices and associated short-range aperiodicity. In quasicrystals, aperiodicity is known to induce pseudo-bandgaps and we suspect a similar phenomenon here.
Article Details
Authors (29)
Andrew Rogers
Kristina Holsgrove
Nils A. Schäfer
Boris Koppitz
Conor J. McCluskey
Shivani Yedama
Ronan Lynch
Keelan Sloan
Barry Porter
Adam Sykes
Alex Catalan Daniels
Romualdo S. Silva
Flavio Y. Bruno
Sam D. Seddon
Haidong Lu
Michael Ruesing
Christa Fink
Philipp Fahler-Muenzer
Sarah Fearn
Sandrine E. M. Heutz
Marios Hadjimichael
Quentin M. Ramasse
Marin Alexe
Amit Kumar
Raymond G. P. McQuaid
Alexei Gruverman
Simone Sanna
Lukas M. Eng
J. Marty Gregg