Papers by Keyword: Disordered Systems

Abstract: In the present paper, we have reported the results of our computational study of phonon frequencies in binary metallic glass CuZr₂. Model potential formalism is used here along with two different approaches namely due to Hubbard and Beeby (HB) as well as due to Takeno and Goda (TG). The results are compared with the recent experimental results and the possible ways of improvements in the results are also discussed. Further, sound velocities are also reported.

Abstract: We used a Monte Carlo simulation of the structurally disordered three dimensional Ising model. For the systems with spin concentrations p = 0.95 ,0.8, 0.6 and 0.5 we calculated the correlation-length critical exponent ν by finite-size scaling. Extrapolations to the thermodynamic limit yield ν(0.95) = 0.705(5) ,ν(0.8) = 0.711(6), ν(0.6) = 0.736(6) and ν(0.5) = 0.744(6). These results are compatible with some previous estimates from a variety of sources. The analysis of the results demonstrates the nonuniversality of the critical behavior in the disordered Ising model.

Abstract: When an STM tip is brought close to a nano sized sample then it can deliver (or draw) a current that is determined by the Landauer-Büttiker formalism in terms of the scattering matrix that gives partial local density of states. We show that, very paradoxically, the interference related term in this formula vanish in a quantum regime making semi-classical formula for injectance exact in some regime. We explicitly show how evanescent modes are responsible for this. This can have useful implications to experimentalists as semi-classical formulas are much simpler.

Abstract: The dynamic critical behavior of the three-dimensional Heisenberg model with longrangecorrelated disorder was studied by using short-time Monte Carlo simulations at criticality.The static and dynamic critical exponents are determined. The simulation was performed fromordered initial state. The obtained values of the exponents are in a good agreement with resultsof the field-theoretic description of the critical behavior of this model in the two-loopapproximation.