Ab initio prediction of stable nanotwin double layers and 4O structure in Ni${}_2$MnGa

Abstract

The ab initio electronic structure calculations of the Ni${}_2$MnGa The alloy indicate that the orthorhombic 4O structure exhibits the lowest energy compared to all known martensitic structures. The 4O structure is formed by nanotwin double layers, i.e., oppositely oriented nanotwins consisting of two (101) lattice planes of nonmodulated martensitic structure. It exhibits the lowest occupation of density of states at the Fermi level. The total energy 1.98 meV/atom below the energy of nonmodulated martensite is achieved within structural relaxation by shifting Mn and Ga atoms at the nanotwin boundaries. The same atomic shift can also be found in other martensitic nanotwinned or modulated structures such as 10M and 14M, which indicates the importance of the nanotwin double layer for the stability of these structures. Our discovery shows that the nanotwinning or modulation is a natural property of low-temperature martensitic phases in Ni-Mn-Ga alloys.

References in corpus (4)

• Adaptive modulations of martensites
• First-principles study of lattice instabilities in the ferromagnetic martensite Ni${}_2$MnGa
• Combined experimental and theoretical investigation of the premartensitic transition in Ni${}_2$MnGa
• A First-Principles Investigation of Phonon Softenings and Lattice Instabilities in the Shape-Memory System Ni${}_2$MnGa

Cited by in corpus (7)

• Modulations in martensitic Heusler alloys originate from nanotwin ordering
• Nucleation and growth of hierarchical martensite in epitaxial shape memory films
• Geometry of Adaptive Martensite in Ni-Mn-based Heusler alloys
• Branching of twins in shape memory alloys revisited
• Interplay of phase sequence and electronic structure in the modulated martensites of Mn${}_2$NiGa from first-principles
• Electronic structure beyond the generalized gradient approximation for Ni${}_2$MnGa
• Shear Deformation of Nonmodulated Ni${}_2$MnGa Martensite: An Ab Initio Study