# Groupe de Physique Statistique

## Equipe 106, Institut Jean Lamour

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### Articles dans des revues à comité de lecture

 Scaling properties at the interface between different critical subsystems: The Ashkin-Teller model Lajko P., Turban L. and Iglói F. Phys. Rev. B 76 (2007) 224423 DOI : 10.1103/PhysRevB.76.224423 ArXiv : arxiv:0709.1322 [PDF] HAL : hal-00421967 We consider two critical semi-infinite subsystems with different critical exponents and couple them through their surfaces. The critical behavior at the interface, influenced by the critical fluctuations of the two subsystems, can be quite rich. In order to examine the various possibilities, we study a system composed of two coupled Ashkin-Teller models with different four-spin couplings $\epsilon$, on the two sides of the junction. By varying $\epsilon$, some bulk and surface critical exponents of the two subsystems are continuously modified, which in turn changes the interface critical behavior. In particular we study the marginal situation, for which magnetic critical exponents at the interface vary continuously with the strength of the interaction parameter. The behavior expected from scaling arguments is checked by DMRG calculations.