Publication details

Phase stability, elasticity, and theoretical strength of polonium from first principles


LEGUT Dominik FRIÁK Martin ŠOB Mojmír

Year of publication 2010
Type Article in Periodical
Magazine / Source Physical Review B
MU Faculty or unit

Faculty of Science

Field Solid matter physics and magnetism
Keywords polonium; phase stability; elasticity; theoretical strength; ab initio calculations
Description We investigate the stability of Po in its ground-state simple cubic structure (alpha-Po) with respect to the trigonal spiral structure exhibited by Se and Te and to the displacive phase transformations into either tetragonal or trigonal phases. The origin of the phase stability of alpha-Po is elucidated and high elastic anisotropy of alpha-Po is explained as a consequence of its simple cubic structure. Finally, an uniaxial tensile test for loading along the [001] and [111] directions is simulated; the corresponding theoretical tensile strengths calculated within the LDA+SO approach amount to 4.2 GPa and 4.7 GPa, respectively, which are the lowest values predicted in an element so far. According to Pugh and Frantsevich criteria, alpha-Po is predicted to be ductile. Also a positive value of the Cauchy pressure confirms the metallic type of interatomic bonding.
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