Abstract
Perovskite oxynitrides, in addition to being promising electrocatalysts and photoabsorbers, present an interesting case study in crystal symmetry. Full or partial ordering of the O and N anions affects global symmetry and influences material performance and functionality; however, anion ordering is challenging to detect experimentally. In this work, we synthesize a novel perovskite oxynitride CaW(O,N)3 and characterize its crystal structure using both X-ray and neutron diffraction. Through co-refinement of the diffraction patterns with a range of literature and theory-derived model structures, we demonstrate that CaW(O,N)3 adopts an orthorhombic Pnma average structure and exhibits octahedral distortion with evidence for preferred anion site occupancy. However, through comparison with a large, low-symmetry unit cell, we identify the presence of disorder that is not fully accounted for by the high-symmetry model. We compare CaW(O,N)3 with SrW(O,N)3 to demonstrate the broader presence of such disorder and identify contrasting features in the electronic structures. This work signifies an updated perspective on the inherent crystal symmetry present in perovskite oxynitrides.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4104-4114 |
| Number of pages | 11 |
| Journal | Materials Horizons |
| Volume | 11 |
| Issue number | 17 |
| DOIs | |
| State | Published - Jun 5 2024 |
Funding
The authors recognize Brian Toby for his insight regarding qualitative and quantitative comparison of structural models. M. E. S. was supported by the Department of Defense (DoD) through the National Defense Science and Engineering Graduate (NDSEG) Fellowship Program. This work made use of the Jerome B. Cohen X-Ray Diffraction Facility supported by the MRSEC program of the NSF (DMR-2308691) at the Materials Research Center of Northwestern University and the SHyNE Resource (NSF ECCS-1542205.) We acknowledge Dr Saul Lapidus and beamline 11-BM at the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. We also acknowledge Dr Qiang Zhang at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This work was supported by the National Science Foundation's MRSEC program (DMR-1720319) at the Materials Research Center of Northwestern University. This work was partially funded by NSF CAREER Award (2144365-CBET). This work made use of the Keck-II facility of Northwestern University's NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the International Institute for Nanotechnology (IIN), and Northwestern's MRSEC program (NSF DMR-2308691). The DFT calculations were performed using computational resources from the Quest high performance computing facility at Northwestern University which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology and also the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231 using NERSC award BES-ERCAP23792.
ASJC Scopus subject areas
- General Materials Science
- Mechanics of Materials
- Process Chemistry and Technology
- Electrical and Electronic Engineering