Giant negative thermal expansion exceeding 1000 K in PrMnO3 via synergy of local structure distortion and orbital disordering
Feiyu Qin, Xiaoya Bai, Yue‐Wen Fang, Pan Zhu, Jun Wang, Pengtao Cheng, Dunhui Wang, Lei Hu, Jun Sun, Xiangdong Ding
Abstract
(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.
Topics & Concepts
Negative thermal expansionThermal expansionCondensed matter physicsThermalMaterials sciencePlanarSynchrotronLocal structureSymmetry breakingLocal symmetrySymmetry (geometry)StoichiometryPhysicsDistortion (music)Contraction (grammar)Thermal fluctuationsControl reconfigurationCrystallographyThermal Expansion and Ionic ConductivityMagnetic and transport properties of perovskites and related materialsHeusler alloys: electronic and magnetic properties