http://www.cnr.it/ontology/cnr/individuo/prodotto/ID213532

Displacive phase transition at the 5/3 monolayer of Pb on Ge(001) (Articolo in rivista)

Type

Label

Displacive phase transition at the 5/3 monolayer of Pb on Ge(001) (Articolo in rivista) (literal)

Anno

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

Alternative label

Cvetko, D Ratto, F Cossaro, A Bavdek, G Morgante, A Floreano, L (2005)
Displacive phase transition at the 5/3 monolayer of Pb on Ge(001)
in Physical review. B, Condensed matter and materials physics (CD-ROM); The American Physical Society, College Park, MD 20740-3844 (Stati Uniti d'America)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

Pagina inizio

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

Rivista

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo

Note

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

Inst Nazl Fis Mat, Lab TASC, Trieste, Italy. Univ Ljubljana, Dept Phys, Ljubljana 61000, Slovenia. Jozef Stefan Inst, Ljubljana, Slovenia. Univ Quebec, INRS Energie, Varennes, PQ, Canada. Univ Trieste, Dept Phys, Trieste, Italy. (literal)

Titolo

Abstract

At a coverage of 5/3 monolayer (ML), Pb adsorbed on Ge(001) forms a ground phase displaying a ((2 1)(0 6))s ymmetry. This phase undergoes two reversible phase transitions ((2 1)(0 6))<->((2 1)(0 3))<->(2x1) at the critical temperatures T(c1)similar to 178 K and T(c2)similar to 375 K, respectively. We investigated the behavior of the relevant order parameters at the critical temperatures by means of He and in-plane x-ray diffraction (HAS and XRD, respectively). Both phase transitions at the critical temperature put in evidence a clear order-disorder behavior, in agreement with the universality class expected for the corresponding symmetry group transformation. The low-temperature transition yields the critical exponent of the two-dimensional (2-D) Ising universality class, whereas the three-state Potts' critical exponents are found for the high-temperature transition. By out-of-plane XRD measurements, the low-temperature phase transition is observed to be accompanied by a static surface distortion at room temperature. A complementary HAS study of the temperature evolution of the surface charge corrugation reveals that the complete ((2 1)(0 6))<->((2 1)(0 3)) transition is of the displacive type. On the contrary, the high-temperature phase transition does not show any change of the surface corrugation up to its irreversible decomposition, thus pointing to a pure order-disorder character. (literal)

Editore