Articles dans des revues à comité de lecture
|Critical behavior at the interface between two systems belonging to different universality classes|
|Bagamery F.A., Turban L., Iglói F.|
|Physical Review B - Condensed Matter and Materials Physics 73 (2006) 144419|
|DOI : 10.1103/PhysRevB.73.144419|
|ArXiv : cond-mat/0601282 [PDF]|
|HAL : hal-00112684|
We consider the critical behavior at an interface which separates two semi-infinite subsystems belonging to different universality classes, thus having different sets of critical exponents, but having a common transition temperature. We solve this problem analytically in the frame of k mean-field theory, which is then generalized using phenomenological scaling considerations. A large variety of interface critical behavior is obtained which is checked numerically on the example of two-dimensional q -state Potts models with 2âo/oo¤qâo/oo¤4. Weak interface couplings are generally irrelevant, resulting in the same critical behavior at the interface as for a free surface. With strong interface couplings, the interface remains ordered at the bulk transition temperature. More interesting is the intermediate situation, the special interface transition, when the critical behavior at the interface involves new critical exponents, which, however, can be expressed in terms of the bulk and surface exponents of the two subsystems. We discuss also the smooth or discontinuous nature of the order parameter profile.