Publication detail

Ab initio prediction of stable nanotwin double layers and 4O structure in Ni2MnG

ZELENÝ, M. STRAKA, L. SOZINOV, A. HECZKO, O.

English title

Ab initio prediction of stable nanotwin double layers and 4O structure in Ni2MnG

Type

journal article in Web of Science

Language

en

Original abstract

The ab initio electronic structure calculations of the Ni2MnGa 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.

English abstract

The ab initio electronic structure calculations of the Ni2MnGa 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.

Keywords in English

Martensitic phase transition, Shape-memory materials, Crystal structures

Released

30.12.2016

ISSN

1098-0121

Volume

94

Number

22

Pages from–to

224108-1–224108-6

Pages count

6

BIBTEX


@article{BUT131035,
  author="Martin {Zelený} and Ladislav {Straka} and Alexei {Sozinov} and Oleg {Heczko},
  title="Ab initio prediction of stable nanotwin double layers and 4O structure in Ni2MnG",
  year="2016",
  volume="94",
  number="22",
  month="December",
  pages="224108-1--224108-6",
  issn="1098-0121"
}