Defect-induced condensation and central peak at structural transitions

dc.contributor.authorSchwabl, Franzen
dc.contributor.authorTäuber, Uwe C.en
dc.contributor.departmentPhysicsen
dc.date.accessioned2016-10-01T15:08:33Zen
dc.date.available2016-10-01T15:08:33Zen
dc.date.issued1991-05-01en
dc.description.abstractWe investigate how the statics and dynamics of distortive phase transitions are influenced by defects which locally increase the transition temperature. In contrast to the local condensation at a single defect, a finite concentration n of randomly distributed defects induces a real phase transition at the temperature T<sub>c</sub>(n). The phonon response function is calculated analytically in single-site approximation. For T > T<sub>c</sub>(n) and low phonon damping we find a soft-phonon impurity band below the continuum, which eventually becomes overdamped when T T<sub>c</sub>(n) and produces a dynamical central peak in the phonon-phonon correlation function. In the case of stronger damping and low defect concentration, the impurity band is masked and only appears as a narrow central peak very close to T<sub>c</sub>(n). We develop a method which allows the computation of the order parameter and the correlation function in random systems. For T << ( T<sub>c</sub>(n), the dynamical central peak disappears in the longitudinal correlation function, while it persists in the transverse components for rotational symmetry. The effect of cubic terms breaking the continuous rotational invariance is also investigated. In any case, the finite order parameter below T<sub>c</sub>(n) produces a static central peak in the dynamical structure factor, which has a finite width in momentum space.en
dc.description.versionPublished versionen
dc.format.extent11112 - 11135 page(s)en
dc.identifier.doihttps://doi.org/10.1103/PhysRevB.43.11112en
dc.identifier.issn0163-1829en
dc.identifier.issue13en
dc.identifier.urihttp://hdl.handle.net/10919/73148en
dc.identifier.volume43en
dc.relation.urihttp://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1991FL04100039&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=930d57c9ac61a043676db62af60056c1en
dc.rightsIn Copyrighten
dc.rights.holderThe American Physical Societyen
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.titleDefect-induced condensation and central peak at structural transitionsen
dc.title.serialPhysical Review Ben
dc.typeArticle - Refereeden
pubs.organisational-group/Virginia Techen
pubs.organisational-group/Virginia Tech/All T&R Facultyen
pubs.organisational-group/Virginia Tech/Scienceen
pubs.organisational-group/Virginia Tech/Science/COS T&R Facultyen
pubs.organisational-group/Virginia Tech/Science/Physicsen

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