Scholarlink

<p>Giant negative thermal expansion (NTE), defined by volumetric expansion α<sub>V</sub> &lt;ca. −50 × 10<sup>−6</sup> K<sup>−1</sup> (volume contraction (Δ<i>V/V</i>) &lt; − 0.5% within ~100 K), is rarely observed at high temperatures. Here, we report a giant NTE persisting above 1000 K (Δ<i>V/V</i> = − 1.7 %, 900–1100 K) in stoichiometric PrMnO<sub>3</sub> (PMON) with a peak coefficient α<sub>V</sub> = − 114 × 10<sup>−6 </sup>K<sup>−1</sup> around 1000 K. Contrastingly, oxygen-rich PrMnO<sub>3+<i>x</i></sub> (PMOA) exhibits only positive thermal expansion. The origin of NTE was uncovered via synchrotron X-ray total scattering, Cs-corrected STEM, and DFT calculations. Intriguingly, PMON uniquely hosts a local symmetry breaking featured by a 3D cross-arranged network of elongated Mn-O bonds, different from the 2D planar configurations in PMOA. By correlating atomic-scale symmetry breaking and thermally activated orbital reconfiguration to macroscopic thermal responses, we establish an unconventional paradigm for engineering giant NTE at elevated temperatures.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Giant negative thermal expansion exceeding 1000 K in PrMnO3 via synergy of local structure distortion and orbital disordering

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年11月13日

查看全文
  • Feiyu Qin,
  • Xiaoya Bai,
  • Yue-Wen Fang,
  • Pengli Zhu,
  • Jun Wang,
  • Pengtao Cheng,
  • Dunhui Wang,
  • Lei Hu,
  • Jun Sun,
  • Xiangdong Ding

摘要

Giant negative thermal expansion (NTE), defined by volumetric expansion αV <ca. −50 × 10−6 K−1 (volume contraction (ΔV/V) < − 0.5% within ~100 K), is rarely observed at high temperatures. Here, we report a giant NTE persisting above 1000 K (ΔV/V = − 1.7 %, 900–1100 K) in stoichiometric PrMnO3 (PMON) with a peak coefficient αV = − 114 × 10−6 K−1 around 1000 K. Contrastingly, oxygen-rich PrMnO3+x (PMOA) exhibits only positive thermal expansion. The origin of NTE was uncovered via synchrotron X-ray total scattering, Cs-corrected STEM, and DFT calculations. Intriguingly, PMON uniquely hosts a local symmetry breaking featured by a 3D cross-arranged network of elongated Mn-O bonds, different from the 2D planar configurations in PMOA. By correlating atomic-scale symmetry breaking and thermally activated orbital reconfiguration to macroscopic thermal responses, we establish an unconventional paradigm for engineering giant NTE at elevated temperatures.