skip to main content

SciTech ConnectSciTech Connect

Title: Cation ordering and effect of biaxial strain in double perovskite CsRbCaZnCl{sub 6}

Here, we investigate the electronic structure, energetics of cation ordering, and effect of biaxial strain on double perovskite CsRbCaZnCl{sub 6} using first-principles calculations based on density functional theory. The two constituents (i.e., CsCaCl{sub 3} and RbZnCl{sub 3}) forming the double perovskite exhibit a stark contrast. While CsCaCl{sub 3} is known to exist in a cubic perovskite structure and does not show any epitaxial strain induced phase transitions within an experimentally accessible range of compressive strains, RbZnCl{sub 3} is thermodynamically unstable in the perovskite phase and exhibits ultra-sensitive response at small epitaxial strains if constrained in the perovskite phase. We show that combining the two compositions in a double perovskite structure not only improves overall stability but also the strain-polarization coupling of the material. Our calculations predict a ground state with P4/nmm space group for the double perovskite, where A-site cations (i.e., Cs and Rb) are layer-ordered and B-site cations (i.e., Ca and Zn) prefer a rocksalt type ordering. The electronic structure and bandgap in this system are shown to be quite sensitive to the B-site cation ordering and is minimally affected by the ordering of A-site cations. We find that at experimentally accessible compressive strains CsRbCaZnCl{sub 6} can be phasemore » transformed from its paraelectric ground state to an antiferroelectric state, where Zn atoms contribute predominantly to the polarization. Furthermore, both energy difference and activation barrier for a transformation between this antiferroelectric state and the corresponding ferroelectric configuration are predicted to be small. The computational approach presented here opens a new pathway towards a rational design of novel double perovskites with improved strain response and functionalities.« less
Authors:
;  [1]
  1. Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
22399307
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CALCIUM COMPOUNDS; CATIONS; CESIUM COMPOUNDS; COUPLING; CUBIC LATTICES; DENSITY FUNCTIONAL METHOD; ELECTRONIC STRUCTURE; EPITAXY; FERROELECTRIC MATERIALS; GROUND STATES; PEROVSKITE; PHASE STABILITY; PHASE TRANSFORMATIONS; POLARIZATION; RUBIDIUM COMPOUNDS; STRAINS; TETRAGONAL LATTICES; ZINC CHLORIDES