Naslov
Collective modes in uniaxial incommensurate-commensurate systems with the real order parameter

Autori
Dananić, Vladimir ; Bjeliš, Aleksa ; Latković, Mladen

Izvornik
Journal of Physics A-Mathematical and general (0305-4470) 33 (2000); 4619-4641

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
incommensurate systems; phase transitions; collective modes

Sažetak
The basic Landau model for uniaxial systems of the II class is nonintegrable, and allows for various stable and metastable periodic configurations, beside that representing the uniform (or dimerized) ordering. In the present paper we complete the analysis of this model by performing the second order variational procedure, and formulating the combined Floquet-Bloch approach to the ensuing nonstandard linear eigenvalue problem. This approach enables an analytic derivation of some general conclusions on the stability of particular states, and on the nature of accompanied collective excitations. Furthermore, we calculate numerically the spectra of collective modes for all states participating in the phase diagram, and analyze critical properties of Goldstone modes at all second order and first order transitions between disordered, uniform and periodic states. In particular it is shown that the Goldstone mode softens as the underlying soliton lattice becomes more and more dilute.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA