Observation of Vortex Domains in a Two-Dimensional Lead Iodide Perovskite Ferroelectric

Abstract

Topological defects, such as vortices and skyrmions, provide a wealth of splendid possibilities for new nanoscale devices because of their marvelous electronic, magnetic, and mechanical behaviors. Recently, great advances have been made in the study of the ferroelectric vortex in conventional perovskite oxides, such as BaTiO3 and BiFeO3. Despite extensive interest, however, no intriguing ferroelectric vortex structures have yet been found in organic–inorganic hybrid perovskites (OIHPs), which are desirable for their mechanical flexibility, ease of fabrication, and low acoustical impedance. We observed the robust vortex–antivortex topological configurations in a two-dimensional (2D) layered OIHP ferroelectric (4,4-DFPD)2PbI4 (4,4-DFPD is 4,4-di­fluoro­piper­idinium). This provides future directions for the study of perovskites and makes it a promising alternative for nanoscale ferroelectric devices in medical, micromechanical, and biomechanical applications.

The First High‐Temperature Supramolecular Radical Ferroics

“…Piezoresponse force microscopy (PFM) has long been accepted as ap owerful technique to visualize the statics and dynamics of ferroic domains at nanoscale in anondestructive way. [27] PFM phase and amplitude signals indicate the local direction of polarization and the relative strength of piezoresponse,r espectively,c onstituting the PFM image.T og et as tatic and dynamic visualization of ferroic domains,w e performed the PFM measurements on the thin film of 1 and 2 at room temperature.F or 1,a ss hown in Figure 4a-c and Figure S9a,b,t he different domain structures in vertical and lateral PFM present am ultiaxial characteristic.S imilarly, 2 also manifests the existence of non-1808 8 domains.Itshould be noted that the non-1808 8 domains may stem from the mechanical stress fields imposed by the indium-doped tin oxide (ITO) glass substrate. [28] Besides the above-mentioned quasi-static method, PFM provides an alternative for the evaluation of piezoelectric response with great efficiency and easy accessibility.T o confirm the obtained d 33 values through quasi-static method, PFM measurements were applied on the (001) surface of single crystals of 1 and 2 at room temperature.I nt his measurement, we applied voltage to the sample surface through the conductive tip in the contact mode and recorded the corresponding piezoresponse as amplitude signal (A).…”

Structural chemistry of layered lead halide perovskites containing single octahedral layers

“…) mode which leads to a polar space group, Aba2 or Cmc2 1 , the former compound has been demonstrated to exhibit ferroelectricity (Zhang, Song, Chen et al, 2020).…”

The First High‐Temperature Supramolecular Radical Ferroics

“…Piezoresponse force microscopy (PFM) has long been accepted as ap owerful technique to visualize the statics and dynamics of ferroic domains at nanoscale in anondestructive way. [27] PFM phase and amplitude signals indicate the local direction of polarization and the relative strength of piezoresponse,r espectively,c onstituting the PFM image.T og et…”