title: Ultrathin Epitaxial Barrier Layer to Avoid Thermally Induced Phase Transformation in Oxide Heterostructures.
abstract: Incorporating oxides with radically different physical and chemical properties into heterostructures offers tantalizing possibilities to derive new functions and structures. Recently, we have fabricated freestanding 2D oxide membranes using the water-soluble perovskite Sr3Al2O6as a sacrificial buffer layer. Here, with atomic-resolution spectroscopic imaging, we observe that direct growth of oxide thin films on Sr3Al2O6can cause complete phase transformation of the buffer layer, rendering it water-insoluble. More importantly, we demonstrate that an ultrathin SrTiO3layer can be employed as an effective barrier to preserve Sr3Al2O6during subsequent growth, thus allowing its integration in a wider range of oxide heterostructures.
authors.forename: David J
authors.identifier: 0000-0002-0922-6773
authors.initials: DJ
authors.lastname: Baek
authors.forename: Di
authors.initials: D
authors.lastname: Lu
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Hikita
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors.forename: Harold Y
authors.initials: HY
authors.lastname: Hwang
authors.forename: Lena F
authors.initials: LF
authors.lastname: Kourkoutis
keywords: STEM-EELS; buffer layers; oxide heterostructures; soft oxides; thermal stability