## Abstract

Zinc-blende (α-) and NiAs-type (β-) MnAs are investigated with a combined first-principles linearized argumented plane wave and DMol^{3} study within both the local density approximation (LDA) and the generalized gradient approximation (GGA). First-principles calculations within the GGA predict the lattice volume for β-MnAs much better than LDA (which underestimates it by 15%) compared with experiment. The LDA calculated equilibrium lattice volume of α-MnAs is 10% smaller than that of GaAs, which is in contradiction to the well-accepted fact that the lattice volume of Ga_{1-x}Mn_{x}As increases with x. In contrast, the GGA predicts a reasonable lattice volume for α-MnAs. The ferromagnetic α-MnAs is shown to be a metal at a= 5.7 Å, and to undergo a transition to a half-metallic phase when it expands to a>5.8 Å due to the decreased bandwidth. Further, the calculated cohesive energy of β-MnAs is nearly 0.87 eV greater than that of α-MnAs, which provides theoretical support for the instability of α-MnAs.

Original language | English (US) |
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Article number | 113202 |

Pages (from-to) | 1132021-1132024 |

Number of pages | 4 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 65 |

Issue number | 11 |

State | Published - Mar 15 2002 |

## ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics