Tetragonal states of palladium I. Theory
Abstract
Firstprinciples totalenergy calculations on the tetragonal states of bulk elemental palladium have been made with a fullpotential electronic structure program with both the localdensity approximation (LDA) and the generalized gradient approximation (GGA). The unique path through tetragonal states produced by epitaxial strain on equilibrium states has been found. This path, called the epitaxial Bain path, shows that bodycentered cubic Pd (axial ratio c/a=1) is unstable, but a shallow energy minimum exists for a bodycentered tetragonal (bct) state with axial ratio c/a~0.9. Structure parameters and elastic constants of both the facecentered cubic (fcc) ground state and the bct state are determined and the fcc values are compared to experiment: the LDA results are better than the GGA results. Tests of the stability of the bct phase at c/a~0.9 show that this phase is unstable with respect to [110] shear in the (001) plane.
 Publication:

Physical Review B
 Pub Date:
 April 2002
 DOI:
 10.1103/PhysRevB.65.155403
 Bibcode:
 2002PhRvB..65o5403J
 Keywords:

 68.55.Nq;
 64.60.My;
 61.66.Bi;
 Composition and phase identification;
 Metastable phases;
 Elemental solids