The cubic-to-orthorhombic structural transition occurring in CsH at a pressure of about 17 GPa is studied by ab initio calculations, The relative stability of the competing structures and the transition pressure are correctly predicted. We show that this pressure-induced first-order transition is intimately related to a displacive second-order transition which would occur upon application of a shear strain to the (110) planes. The resulting instability is rationalized in terms of the pressure-induced modifications of the electronic structure.
|Titolo:||Phonon softening and elastic instabilities in the cubic-to-orthorhombic structural transition of CsH|
|Autori:||Saitta, A. M.; Alfè, D.; De Gironcoli, S.; Baroni, S.|
|Data di pubblicazione:||1997|
|Digital Object Identifier (DOI):||10.1103/PhysRevLett.78.4958|
|Appare nelle tipologie:||1.1 Journal article|