Ab initio výpočet elastických a magnetických vlastností krstalů Fe, Co, Ni a Cr při izotropní deformaci

Ab initio calculations of elastic and magnetic properties of Fe, Co, Ni, and Cr crystals under isotropic deformation

článek v časopise ve Web of Science, Jimp

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Ab initio electronic structure calculations of the ideal strength of Fe, Co, Ni, and Cr under isotropic tension were performed using the linear muffin-tin orbital method in the atomic sphere approximation. Magnetic ordering was taken into account by means of a spin-polarized calculation. Two approximations for the exchange-correlation term were employed: namely, the local (spin) density approximation and the generalized gradient approximation. Computed values of equilibrium lattice parameters, bulk moduli, and magnetic moments were compared with available experimental data. The stability of the ground-state structure in the tensile region was assessed via comparison of its total energy and enthalpy with those of some other structures. No instabilities were found before reaching the inflection point on the total energy versus volume curve and the stress related to this point was therefore considered to be the ideal strength.

Ab initio electronické strukturní výpočty ideální pevnosti Fe, Co, Ni, a Cr za isotropního tahu byly provedeny použitím linear muffin-tin orbital metody v rámci atomic sphere approximation. Magnetické uspořádání bylo vzato v úvahu prostřednictvím spin-polarized calculation. Dvě aproximace pro exchange-correlation člen byly použity: local (spin) density approximation a generalized gradient approximation. Spočtené hodnoty rovnovážného mřížkového parametru, modulu objemové pružnosti a magnetických momentů byly porovnány s dostupnými experimentálními daty. Stabilita struktury základního stavu v tahové oblasti byla ověřena porovnáním její celkové energie a entalpie s hodnotami pro jiné struktury. Žádné nestability nebyly nalezeny až do dosažení inflexního bodu na křivce záviclosti energie na objemu a napětí odpovídající tomuto bodu bylo považováno za teoretickou pevnost.

Ab initio electronic structure calculations of the ideal strength of Fe, Co, Ni, and Cr under isotropic tension were performed using the linear muffin-tin orbital method in the atomic sphere approximation. Magnetic ordering was taken into account by means of a spin-polarized calculation. Two approximations for the exchange-correlation term were employed: namely, the local (spin) density approximation and the generalized gradient approximation. Computed values of equilibrium lattice parameters, bulk moduli, and magnetic moments were compared with available experimental data. The stability of the ground-state structure in the tensile region was assessed via comparison of its total energy and enthalpy with those of some other structures. No instabilities were found before reaching the inflection point on the total energy versus volume curve and the stress related to this point was therefore considered to be the ideal strength.

ab initio calculation, elastic and magnetic properties, isotropic deformations, spin-polarization

2003

30.01.2003

AMERICAN PHYSICAL SOC

USA

1098-0121

PHYSICAL REVIEW B

67

1

035116-1–035116-8

8