Structural phase transition of gold under uniaxial, tensile, and triaxial stresses: An ab initio study


Durandurdu M.

PHYSICAL REVIEW B, cilt.76, 2007 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

The behavior of gold crystal under uniaxial, tensile, and three different triaxial stresses is studied using an ab initio constant pressure technique within a generalized gradient approximation. Gold undergoes a phase transformation from the face-centered-cubic structure (fcc) to a body-centered-tetragonal (bct) structure having the space group of I4/mmm with the application of uniaxial stress, while it transforms to a face-centered-tetragonal (fct) phase within I4/mmm symmetry under uniaxial tensile loading. Further uniaxial compression of the bct phase results in a symmetry change from I4/mmm to P-1 at high stresses and ultimately structural failure around 200.0 GPa. For the case of triaxial stresses, gold also converts into a bct state. The critical stress for the fcc-to-bct transformation increases as the ratio of the triaxial stress increases. Both fct and bct phases are elastically unstable.