TY - JOUR

T1 - Orientational twins in an improper ferroelastic phase transition driven by the (formula presented) zone-boundary phonon in (formula presented)

AU - Hatch, Dorian M.

AU - Cao, Wenwu

AU - Saxena, Avadh

PY - 2002

Y1 - 2002

N2 - Orientational twins involve two domain states that exhibit rotational symmetry relationships between them. For an improper ferroelastic cubic to tetragonal first-order phase transition driven by the (formula presented) zone-boundary phonon in the CsCl structure, there are three possible directions for the tetragonal axis of the low-temperature phases. The existence of four antiphase-related-domain states for each given tetragonal orientation introduces additional possible pairing schemes for the twins. We obtain only three distinct domain pair classes: two antiphase boundary classes and one orientational boundary class. For this (formula presented) (formula presented) transition we derive the general governing equations for the orientational twins based on a Ginzburg-Landau theory, which constitute a system of four coupled nonlinear differential equations. General features of the orientational twin solutions are demonstrated through a special choice of the parameters for which the four coupled equations can be reduced to two. The orientational twin boundaries have relatively large elastic energy and, therefore, they are strongly restricted to preferred lattice planes.

AB - Orientational twins involve two domain states that exhibit rotational symmetry relationships between them. For an improper ferroelastic cubic to tetragonal first-order phase transition driven by the (formula presented) zone-boundary phonon in the CsCl structure, there are three possible directions for the tetragonal axis of the low-temperature phases. The existence of four antiphase-related-domain states for each given tetragonal orientation introduces additional possible pairing schemes for the twins. We obtain only three distinct domain pair classes: two antiphase boundary classes and one orientational boundary class. For this (formula presented) (formula presented) transition we derive the general governing equations for the orientational twins based on a Ginzburg-Landau theory, which constitute a system of four coupled nonlinear differential equations. General features of the orientational twin solutions are demonstrated through a special choice of the parameters for which the four coupled equations can be reduced to two. The orientational twin boundaries have relatively large elastic energy and, therefore, they are strongly restricted to preferred lattice planes.

UR - http://www.scopus.com/inward/record.url?scp=85038347115&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85038347115&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.65.094110

DO - 10.1103/PhysRevB.65.094110

M3 - Article

AN - SCOPUS:85038347115

SN - 1098-0121

VL - 65

SP - 1

EP - 11

JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

IS - 9

ER -