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

0349231 - ÚFM 2011 RIV US eng J - Článek v odborném periodiku
Legut, Dominik - Friák, Martin - Šob, Mojmír
Phase stability, elasticity, and theoretical strength of polonium from first principles.
Physical Review. B. Roč. 81, č. 21 (2010), 214118/1/-214118/19/. ISSN 1098-0121
Grant CEP: GA AV ČR IAA100100920; GA MŠMT(CZ) OC10008
Výzkumný záměr: CEZ:AV0Z20410507
Klíčová slova: polonium * phase stability * elasticity * theoretical strength * ab initio calculations
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 3.772, rok: 2010

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.
Trvalý link: http://hdl.handle.net/11104/0189527