Robust high pressure stability and negative thermal expansion in sodium-rich antiperovskites Na{sub 3}OBr and Na{sub 4}OI{sub 2}

Journal Article · Thu Jan 14 00:00:00 EST 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4940020· OSTI ID:22494920

Wang, Yonggang ^[1]; Wen, Ting ^[2]; Park, Changyong; Kenney-Benson, Curtis ^[3]; Pravica, Michael; Zhao, Yusheng ^[1]; Yang, Wenge ^[4]

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1. High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154 (United States)
2. Institute of Nanostructured Functional Materials, Huanghe Science and Technology College, Zhengzhou, Henan 450006 (China)
3. High Pressure Collaborative Access Team (HPCAT), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States)
4. High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States)

The structure stability under high pressure and thermal expansion behavior of Na{sub 3}OBr and Na{sub 4}OI{sub 2}, two prototypes of alkali-metal-rich antiperovskites, were investigated by in situ synchrotron X-ray diffraction techniques under high pressure and low temperature. Both are soft materials with bulk modulus of 58.6 GPa and 52.0 GPa for Na{sub 3}OBr and Na{sub 4}OI{sub 2}, respectively. The cubic Na{sub 3}OBr structure and tetragonal Na{sub 4}OI{sub 2} with intergrowth K{sub 2}NiF{sub 4} structure are stable under high pressure up to 23 GPa. Although being a characteristic layered structure, Na{sub 4}OI{sub 2} exhibits nearly isotropic compressibility. Negative thermal expansion was observed at low temperature range (20–80 K) in both transition-metal-free antiperovskites for the first time. The robust high pressure structure stability was examined and confirmed by first-principles calculations among various possible polymorphisms qualitatively. The results provide in-depth understanding of the negative thermal expansion and robust crystal structure stability of these antiperovskite systems and their potential applications.

• OSTI ID: 22494920
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 2; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPRESSIBILITY
CRYSTAL STRUCTURE
MATERIALS
PRESSURE RANGE GIGA PA
SODIUM
STABILITY
TEMPERATURE RANGE 0065-0273 K
THERMAL EXPANSION
TRANSITION ELEMENTS
X-RAY DIFFRACTION