Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 9933-9942 |
| Seitenumfang | 10 |
| Fachzeitschrift | Journal of Physics Condensed Matter |
| Jahrgang | 11 |
| Ausgabenummer | 49 |
| Publikationsstatus | Veröffentlicht - 13 Dez. 1999 |
| Veranstaltung | 1999 Workshop on Thin Films and Phase Transitions on Surface - Pamporov, Bulgarien Dauer: 21 Feb. 1999 → 26 Feb. 1999 |
Abstract
Using low-energy electron diffraction (LEED), we show for two classes of systems, which are representative for second- and first-order phase transitions in adsorbed layers, that quantitative properties of phase transitions can be studied also by using integrated diffracted intensities, turning the instrument to low resolution in two-dimensional reciprocal space, k∥. For the continuous order-disorder phase transitions of several atomic adsorption systems, critical properties have been studied by determination of the critical exponents α (of the specific heat) and η, the anomalous critical dimension, in the limit k∥ξ ≫ 1. We performed systematic tests of the conditions under which these exponents can be determined reliably from the diffracted intensity of superstructure beams. In first-order phase transitions, scaling laws characterize specific mechanisms driving the transitions. As an example of two-dimensional first-orderphase transitions, the transitions between a two-dimensional (2D) gas and the 2D solid of the first monolayer have been studied for the noble gases Ar, Kr and Xe on a NaCl(100) surface in quasi-equilibrium with the three-dimensional (3D) gas phase. Using linear temperature ramps, we show that the widths of the hysteresis loops of these transitions as a function of the heating rate, r, scale with a power law ∝rx with x between 0.4 and 0.5 depending on the system. The hysteresis loops for different heating rates are similar. The island area of the condensed layer was found to grow initially with a time dependence ∝t4. These results are in agreement with a model of growth-controlled hysteresis, which predicts x = 0.5 and hysteresis loop similarity.
ASJC Scopus Sachgebiete
- Werkstoffwissenschaften (insg.)
- Allgemeine Materialwissenschaften
- Physik und Astronomie (insg.)
- Physik der kondensierten Materie
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in: Journal of Physics Condensed Matter, Jahrgang 11, Nr. 49, 13.12.1999, S. 9933-9942.
Publikation: Beitrag in Fachzeitschrift › Konferenzaufsatz in Fachzeitschrift › Forschung › Peer-Review
}
TY - JOUR
T1 - Quantitative studies of two-dimensional first- and second-order phase transitions by integrating diffraction methods
AU - Pfnür, Herbert
AU - Voges, C.
AU - Budde, K.
AU - Lyuksyutov, I.
AU - Everts, H. U.
PY - 1999/12/13
Y1 - 1999/12/13
N2 - Using low-energy electron diffraction (LEED), we show for two classes of systems, which are representative for second- and first-order phase transitions in adsorbed layers, that quantitative properties of phase transitions can be studied also by using integrated diffracted intensities, turning the instrument to low resolution in two-dimensional reciprocal space, k∥. For the continuous order-disorder phase transitions of several atomic adsorption systems, critical properties have been studied by determination of the critical exponents α (of the specific heat) and η, the anomalous critical dimension, in the limit k∥ξ ≫ 1. We performed systematic tests of the conditions under which these exponents can be determined reliably from the diffracted intensity of superstructure beams. In first-order phase transitions, scaling laws characterize specific mechanisms driving the transitions. As an example of two-dimensional first-orderphase transitions, the transitions between a two-dimensional (2D) gas and the 2D solid of the first monolayer have been studied for the noble gases Ar, Kr and Xe on a NaCl(100) surface in quasi-equilibrium with the three-dimensional (3D) gas phase. Using linear temperature ramps, we show that the widths of the hysteresis loops of these transitions as a function of the heating rate, r, scale with a power law ∝rx with x between 0.4 and 0.5 depending on the system. The hysteresis loops for different heating rates are similar. The island area of the condensed layer was found to grow initially with a time dependence ∝t4. These results are in agreement with a model of growth-controlled hysteresis, which predicts x = 0.5 and hysteresis loop similarity.
AB - Using low-energy electron diffraction (LEED), we show for two classes of systems, which are representative for second- and first-order phase transitions in adsorbed layers, that quantitative properties of phase transitions can be studied also by using integrated diffracted intensities, turning the instrument to low resolution in two-dimensional reciprocal space, k∥. For the continuous order-disorder phase transitions of several atomic adsorption systems, critical properties have been studied by determination of the critical exponents α (of the specific heat) and η, the anomalous critical dimension, in the limit k∥ξ ≫ 1. We performed systematic tests of the conditions under which these exponents can be determined reliably from the diffracted intensity of superstructure beams. In first-order phase transitions, scaling laws characterize specific mechanisms driving the transitions. As an example of two-dimensional first-orderphase transitions, the transitions between a two-dimensional (2D) gas and the 2D solid of the first monolayer have been studied for the noble gases Ar, Kr and Xe on a NaCl(100) surface in quasi-equilibrium with the three-dimensional (3D) gas phase. Using linear temperature ramps, we show that the widths of the hysteresis loops of these transitions as a function of the heating rate, r, scale with a power law ∝rx with x between 0.4 and 0.5 depending on the system. The hysteresis loops for different heating rates are similar. The island area of the condensed layer was found to grow initially with a time dependence ∝t4. These results are in agreement with a model of growth-controlled hysteresis, which predicts x = 0.5 and hysteresis loop similarity.
UR - http://www.scopus.com/inward/record.url?scp=24044447654&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/11/49/311
DO - 10.1088/0953-8984/11/49/311
M3 - Conference article
AN - SCOPUS:24044447654
VL - 11
SP - 9933
EP - 9942
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
SN - 0953-8984
IS - 49
T2 - 1999 Workshop on Thin Films and Phase Transitions on Surface
Y2 - 21 February 1999 through 26 February 1999
ER -