Determination of lateral interaction energies in AgAu alloy films on Ru(0001) by Monte Carlo simulations

1998 ◽  
Vol 108 (10) ◽  
pp. 4248-4256 ◽  
Author(s):  
J. Michels ◽  
K. Wandelt
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Lateral Interaction ◽  
Interaction Energies ◽  
Alloy Films

The electron transport that occurs within wurtzite zinc oxide and the application of stress

MRS Advances ◽  
2017 ◽  
Vol 2 (48) ◽  
pp. 2627-2632 ◽  
Author(s):  
Poppy Siddiqua ◽  
Michael S. Shur ◽  
Stephen K. O’Leary
Keyword(s):  
Monte Carlo ◽  
Zinc Oxide ◽  
Electron Transport ◽  
Velocity Field ◽  
Monte Carlo Simulations ◽  
Significant Role ◽  
Energy Gap ◽  
Device Application ◽  
The Impact

ABSTRACTWe examine how stress has the potential to shape the character of the electron transport that occurs within ZnO. In order to narrow the scope of this analysis, we focus on a determination of the velocity-field characteristics associated with bulk wurtzite ZnO. Monte Carlo simulations of the electron transport are pursued for the purposes of this analysis. Rather than focusing on the impact of stress in of itself, instead we focus on the changes that occur to the energy gap through the application of stress, i.e., energy gap variations provide a proxy for the amount of stress. Our results demonstrate that stress plays a significant role in shaping the form of the velocity-field characteristics associated with ZnO. This dependence could potentially be exploited for device application purposes.

Triple-Defect B2 Binary Intermetallics: Bragg-Williams Solution and Monte Carlo Simulations

2009 ◽  
Vol 289-292 ◽  
pp. 361-368 ◽  
Author(s):  
Andrzej Biborski ◽  
L. Zosiak ◽  
Rafal Abdank-Kozubski
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Vacancy Concentration ◽  
A Priori ◽  
Equilibrium Concentration ◽  
Pair Interaction ◽  
Type Model ◽  
Interaction Energies ◽  
Atomic Pair ◽  
Antisite Defects

Surprisingly low rate of “order-order” kinetics in stoichiometric NiAl intermetallic known of very high vacancy concentration suggested a specific triple-defect mechanism of ordering/disordering in this system [1]. This mechanism implies a correlation between the concentrations of antisite defects and vacancies; the latters being trapped in triple defects and thus, inactive as atomic migration agents. The process was modelled by means of Monte Carlo (MC) simulations recognised as a powerful tool for such tasks [2], but requiring now the implementation of thermal vacancy thermodynamics. Temperature dependence of vacancy concentration in an AB B2 binary system was determined within an Ising-type model solved first in Bragg-Williams approximation [3] and then by means of MC simulation of a Grandcanonical Ensemble. Without any a priori assumptions concerning the formation of particular types of point defects the model yielded temperature domains where the concentrations of antisite defects and vacancies were proportional. The effect associated with the formation of triple defects appeared for specific values of atomic pair-interaction energies. Moreover, non-stoichiometric A-B systems with the same atomic pair-interaction energies showed the existence of constitutional vacancies at low temperatures. Monte Carlo simulations of “order-order” (disordering) kinetics in B2 AB systems modelled with triple-defect-promoting atomic pair-interaction energies were run with temperature-dependent concentra-tion (i.e. number) of vacancies given by the above model. The simulated relaxations showed two stages: (i) rapid formation of triple defects engaging almost all vacancies present in the system, (ii) very slow process of further generation of antisite defects until the equilibrium concentration was reached. The result reproduced very well the experimental observations [1].

scholarly journals The equation of state with non-equilibrium methods

2018 ◽  
Vol 175 ◽  
pp. 07028 ◽  
Author(s):  
Alessandro Nada ◽  
Michele Caselle ◽  
Marco Panero
Keyword(s):  
Monte Carlo ◽  
Equation Of State ◽  
Monte Carlo Simulations ◽  
Large Set ◽  
Yang Mills ◽  
Novel Technique ◽  
Lattice Gauge ◽  
Lattice Gauge Theories ◽  
Jarzynski’S Equality

Jarzynski’s equality provides an elegant and powerful tool to directly compute differences in free energy in Monte Carlo simulations and it can be readily extended to lattice gauge theories to compute a large set of physically interesting observables. In this talk we present a novel technique to determine the thermodynamics of stronglyinteracting matter based on this relation, which allows for a direct and efficient determination of the pressure using out-of-equilibrium Monte Carlo simulations on the lattice. We present results for the equation of state of the SU(3) Yang-Mills theory in the confined and deconfined phases. Finally, we briefly discuss the generalization of this method for theories with fermions, with particular focus on the equation of state of QCD.

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