Buffer-free exfoliation of Pb-based perovskite oxide membranes

Ultrathin freestanding complex oxide systems have offered new regime of exploration for their viability for commercial devices. However, general exfoliation methods have involved insertion of a foreign epitaxial buffer layer in between the epilayers and substrates, making growth as well as utilization of such membranes a significant challenge. Here, we introduce a new materials combination, including that of lead (Pb), which offers an unprecedented 'buffer-free' exfoliation method enabling atomic precision lift-off of oxide membranes. Through both theoretical frameworks and experiments, we have uncovered the significant role of lead in interface weakening. Using this method, we demonstrate the exfoliation of sub-10 nanometer PMN-PT membrane exhibiting a record-high pyroelectric coefficient, with which we show great possibility of fabricating lightweight, cooling-free far-infrared detectors.