Theory and experimental evidence of phonon domains and their roles in pre-martensitic phenomena

作     者：Yongmei M Jin Yu U Wang Yang Ren 

作者机构：Department of Materials Science and EngineeringMichigan Technological UniversityHoughtonMIUSA X-Ray Science DivisionAdvanced Photon SourceArgonne National LaboratoryArgonneILUSA 

出 版 物：《npj Computational Materials》 (计算材料学（英文）)

年 卷 期：2015年第1卷第1期

页      面：1-14页

核心收录：

学科分类：07[理学] 070202[理学-粒子物理与原子核物理] 0702[理学-物理学] 

基　　金：Supports from NSF DMR-1409317(YMJ) DMR-1506936(YUW)are acknowledged supported by DOE DE-AC02-06CH11357 

主　　题：phonon incomplete crystal 

摘      要：Pre-martensitic phenomena,also called martensite precursor effects,have been known for decades while yet remain outstanding *** paper addresses pre-martensitic phenomena from new theoretical and experimental perspectives.A statistical mechanics-based Grüneisen-type phonon theory is *** the basis of deformation-dependent incompletely softened low-energy phonons,the theory predicts a lattice instability and pre-martensitic transition into elastic-phonon domains via‘phonon spinodal decomposition.’The phase transition lifts phonon degeneracy in cubic crystal and has a nature of phonon pseudo-Jahn–Teller lattice *** theory and notion of phonon domains consistently explain the ubiquitous pre-martensitic anomalies as natural consequences of incomplete phonon *** phonon domains are characterised by broken dynamic symmetry of lattice vibrations and deform through internal phonon relaxation in response to stress(a particular case of Le Chatelier’s principle),leading to previously unexplored new domain *** evidence of phonon domains is obtained by in situ three-dimensional phonon diffuse scattering and Bragg reflection using high-energy synchrotron X-ray single-crystal diffraction,which observes exotic domain phenomenon fundamentally different from usual ferroelastic domain switching *** light of the theory and experimental evidence of phonon domains and their roles in pre-martensitic phenomena,currently existing alternative opinions on martensitic precursor phenomena are revisited.