"Fraternal-twin” ferroelectricity: competing polar states in hydrogen-doped samarium nickelate from first principles

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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Kotiuga, Michele</dc:creator>
  <dc:creator>Rabe, Karin M.</dc:creator>
  <dc:date>2024-04-23</dc:date>
  <dc:description>This work explores hydrogen-doped samarium nickelate from first-principles calculations. At a concentration of 1/4 hydrogen per formula unit we find a number of polar states due to the presence of the interstitial hydrogen. Physically, the polarization of the material arises from the localization of the hydrogen's valence electron on a nearby nickel-oxygen octahedron leading to a local dipole. Due to the inherent tilt pattern present in samarium nickelate, a perovskite with an a-a-c+ tilt pattern, there is an insurmountable energy barrier to switch a given polar state the structure related by inversion symmetry. Instead, we use an in-plane epitaxial constraint to tune the total energy of two structures to be equal. These two structures, unrelated by a cell-symmetry operation, have similar a similar position of the interstitial hydrogen atom, but the valence electron localizes on a different nickel-oxygen octahedron leading to different polarizations. We find that there is a surmountable energy barrier to switch between these two structures.</dc:description>
  <dc:identifier>https://materialscloud-archive-failover.cineca.it/record/2024.62</dc:identifier>
  <dc:identifier>doi:10.24435/materialscloud:tg-8p</dc:identifier>
  <dc:identifier>mcid:2024.62</dc:identifier>
  <dc:identifier>oai:materialscloud.org:1126</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Materials Cloud</dc:publisher>
  <dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
  <dc:rights>Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode</dc:rights>
  <dc:subject>Ferroelectricty</dc:subject>
  <dc:subject>Rare-earth nickelates</dc:subject>
  <dc:subject>Charge localization</dc:subject>
  <dc:title>"Fraternal-twin” ferroelectricity:  competing polar states in hydrogen-doped samarium nickelate from first principles</dc:title>
  <dc:type>Dataset</dc:type>
</oai_dc:dc>