Elastic properties of Mg(1-x)AlxB2

• Elastic properties ofMg(1−x)AlxB2 have been studied from first principles. Theelastic constants (c11, c12, c13, c33 and c55) have been calculated, in the regimeof x = 0 to 0.25. From these calculations the ratio between the bulk modulusand shear modulus (B/G) as well as the ratio between the two directionalbulk moduli (Ba/Bc) have been evaluated. Our calculations show that theratio Ba/Bc decreases monotonically as the aluminium content is increased,whereas the ratio B/G is well below the empirical ductility limit, 1.75, for allconcentrations. In addition, we analyse the electronic structure and the natureof the chemical bonding, using the balanced crystal orbital overlap population(BCOOP) (Grechnev et al 2003 J. Phys.: Condens. Matter 15 7751) and thecharge densities. Our analysis suggests that, while aluminium doping decreasesthe elastic anisotropy of MgB2 in the a and c directions, it will not change thebrittle behaviour of the material considerably.(Some figures in this article are in colour only in the electronic version)

Subject headings

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Keyword

Condensed matter physics

Kondenserade materiens fysik

Publication and Content Type

ref (subject category)

art (subject category)