### Abstract

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 M^{-}_{5} zone-boundary phonon in the CsCI 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 O_{h}^{1}-D_{4h}^{17} (Pm3̄m-14/mmm) 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.

Original language | English (US) |
---|---|

Article number | 094110 |

Pages (from-to) | 941101-9411011 |

Number of pages | 8469911 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 65 |

Issue number | 9 |

State | Published - Mar 1 2002 |

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### All Science Journal Classification (ASJC) codes

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

### Cite this

_{5}

^{-}zone-boundary phonon in RAg

_{1-x}In

_{x}.

*Physical Review B - Condensed Matter and Materials Physics*,

*65*(9), 941101-9411011. [094110].

}

_{5}

^{-}zone-boundary phonon in RAg

_{1-x}In

_{x}',

*Physical Review B - Condensed Matter and Materials Physics*, vol. 65, no. 9, 094110, pp. 941101-9411011.

**Orientational twins in an improper ferroelastic phase transition driven by the M _{5}^{-} zone-boundary phonon in RAg_{1-x}In_{x}.** / Hatch, Dorian M.; Cao, Wenwu; Saxena, Avadh.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Orientational twins in an improper ferroelastic phase transition driven by the M5- zone-boundary phonon in RAg1-xInx

AU - Hatch, Dorian M.

AU - Cao, Wenwu

AU - Saxena, Avadh

PY - 2002/3/1

Y1 - 2002/3/1

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 M-5 zone-boundary phonon in the CsCI 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 Oh1-D4h17 (Pm3̄m-14/mmm) 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 M-5 zone-boundary phonon in the CsCI 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 Oh1-D4h17 (Pm3̄m-14/mmm) 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=0036497355&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036497355&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0036497355

VL - 65

SP - 941101

EP - 9411011

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 9

M1 - 094110

ER -

_{5}

^{-}zone-boundary phonon in RAg

_{1-x}In

_{x}. Physical Review B - Condensed Matter and Materials Physics. 2002 Mar 1;65(9):941101-9411011. 094110.