Effect of random quenched impurities on the critical behavior of a four-state Potts system in two dimensions: An experimental study

Schwenger, L.; Budde, K.; Voges, C.; Pfnür, H.

doi:10.1103/physrevlett.73.296

Cited by 61 publications

(50 citation statements)

References 24 publications

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“…The crystal used for these experiments was cut from a different crystal rod than that used in previous experiments 32 and was supplied by a different manufacturer. We therefore expect that, even if there were some influence by impurities, it should be different on the various samples used.…”

Section: O/ni(111)-p"2ϫ2)mentioning

confidence: 99%

Experimental determination of the phase-transition critical exponentsαandηby integrating methods

Voges

Pfnür

1998

Phys. Rev. B

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Integrating methods in low-energy electron diffraction-turning the instrument to low resolution in k ʈ -can reliably be used to study critical properties of continuous two-dimensional phase transitions and to determine critical exponents ␣ and . We performed systematic tests of the conditions under which an energylike power dependence of the diffracted intensity of superstructure beams can be observed in order-disorder phase transitions of adsorbed atomic layers belonging to three-and four-state Potts universality classes. As experimental examples, we studied the systems p(2ϫ2)-and (ͱ3ϫͱ3)R30°-S/Ru͑0001͒ and (2ϫ2)-2H/Ni͑111͒. We show that above T c the condition for an energylike singularity, K I ӷ1 (K I : radius of integration in k space, : correlation length͒ is already reached at K I Ͼ3, whereas below T c effective exponents ␣ are already obtained for K I Ͻ1. Therefore, in the temperature range below T c this method to determine ␣ turns out to be particularly easy to apply, and we concentrate on the determination of ␣ below T c in this study. Values of ␣ of 0.67Ϯ0.04 and 0.40Ϯ0.05 were obtained for four-state Potts and three-state Potts systems, respectively. The latter value indicates small crossover effects to the critical behavior of the peak intensity. These studies were then further extended to the order-disorder transition of p(2ϫ2)-O/Ni͑111͒, which is weakly first order, and to the effects of oxygen impurities in the system (2ϫ2)-2H/Ni͑111͒. We further show that in the limit kӷ1 the exponent can be determined from the k ʈ dependence of integrated ring intensities around positions of superstructure beams. With the systems mentioned, we demonstrate that the limit of a leading term of critical scattering which is independent of temperature can be reached by carrying out measurements going through the order-disorder phase transitions. Values of of 0.27Ϯ0.10 and of 0.30Ϯ0.10 were obtained for the four-state and the three-state Potts systems, in close agreement with theoretical expectations.

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Section: O/ni(111)-p"2ϫ2)mentioning

confidence: 99%

Experimental determination of the phase-transition critical exponentsαandηby integrating methods

Voges

Pfnür

1998

Phys. Rev. B

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“…wherein the values of the critical exponents (β, γ , ν) change from those of the four-state Potts universality class to Ising-like exponents close to T c [31]. Dotsenko and Dotsenko (DD) [2], in their seminal papers, pioneered the theoretical research of diluted systems; they predicted new critical behavior for the specific heat, magnetization, correlation length and susceptibility, namely,…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo analysis of the critical properties of the two-dimensional randomly bond-diluted Ising model via Wang–Landau algorithm

Hadjiagapiou

2011

Physica A: Statistical Mechanics and its Applications

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“…Impurities can also change first order transitions to second order [2], to the extent that in two dimensions there are no discontinuous phase transitions [3]. There is a growing body of numerical [4] and experimental [5] evidence that, at least in some situations, the asymptotic criticality is similar to the random bond Ising model, irrespective of the underlying symmtery. Here we provide some justification for this observation based on an unexpected universality of the critical interface in the presence of strong bond randomness.…”

mentioning

confidence: 99%

Unusual universality of branching interfaces in random media

et al. 1995

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We study the criticality of a Potts interface by introducing a froth model which, unlike its SOS Ising counterpart, incorporates bubbles of different phases. The interface is fractal at the phase transition of a pure system. However, a position space approximation suggests that the probability of loop formation vanishes marginally at a transition dominated by strong random bond disorder. This implies a linear critical interface, and provides a mechanism for the conjectured equivalence of critical random Potts and Ising models.

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Effect of random quenched impurities on the critical behavior of a four-state Potts system in two dimensions: An experimental study

Cited by 61 publications

References 24 publications

Experimental determination of the phase-transition critical exponentsαandηby integrating methods

Experimental determination of the phase-transition critical exponentsαandηby integrating methods

Monte Carlo analysis of the critical properties of the two-dimensional randomly bond-diluted Ising model via Wang–Landau algorithm

Unusual universality of branching interfaces in random media

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