Density functional theory investigation on lattice dynamics,elastic properties and origin of vanished magnetism in Heusler compounds CoMnVZ (Z =Al,Ga)

• 作者: Guijiang Li Enke Liu Guodong Liu Wenhong Wang Guangheng Wu
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: ATOMIC AND MOLECULAR PHYSICS
• 页码范围: 339-350
• 页数: 12页
• 语种: 英文
• DOI: 10.1088/1674-1056/ac0a6a

摘要

The lattice dynamics,elastic properties and the origin of vanished magnetism in equiatomic quaternary Heusler com-pounds CoMnVZ (Z =Al,Ga) are investigated by first principle calculations in this work.Due to the similar constituent atoms in CoMnVAl and CoMnVGa compounds,they are both stable in LiMgPdSn-type structure with comparable lat-tice size,phonon dispersions and electronic structures.Comparatively,we find that CoMnVAl is more structurally stable than CoMnVGa.Meanwhile,the increased covalent bonding component in CoMnVAl enhances its mechanical strength and Vickers hardness,which leads to better comprehensive mechanical properties than those of CoMnVGa.Practically and importantly,structural and chemical compatibilities at the interface make non-magnetic semiconductor CoMnVAl and magnetic topological semimetals Co2MnAl/Ga more suitable to be grown in heterostructures.Owing to atomic preferen-tial occupation in CoMnVAl/Ga,the localized atoms Mn occupy C (0.5,0.5,0.5) Wyckoff site rather than B (0.25,0.25,0.25) and D (0.75,0.75,0.75) Wyckoff sites in LiMgPdSn-type structure,which results in symmetric band filling and consequently drives them to be non-magnetic.Correspondingly,by tuning localized atoms Mn to occupy B (0.25,0.25,0.25) or/and D (0.75,0.75,0.75) Wyckoff sites in off-stoichiometric Co-Mn-V-Al/Ga compounds and keeping the total valence electrons as 24,newly compensated ferrimagnetic compounds are theoretically achieved.We hope that our work will provide more choices for spintronic applications.