arXiv subjects

Hari M. Koduvely

Publications and source records attributed to Hari M. Koduvely.

3 recordsLinked to original sources

arXiv1999

Epitaxial Growth Kinetics with Interacting Coherent Islands

The Stranski-Krastanov growth kinetics of undislocated (coherent) 3-dimensional islands is studied with a self-consistent mean field rate theory that takes account of elastic interactions between the islands. The latter are presumed to facilitate the detachment of atoms from the islands with a consequent decrease in their average size. Semi-quantitative agreement with experiment is found for the time evolution of the total island density and the mean island size. When combined with scaling ideas, these results provide a natural way to understand the often-observed initial increase and subsequent decrease in the width of the coherent island size distribution.

cond-mat.stat-mech↗

arXiv1997

Numerical Study of Local and Global Persistence in Directed Percolation

The local persistence probability P_l(t) that a site never becomes active up to time t, and the global persistence probability P_g(t) that the deviation of the global density from its mean value rho(t)-<ρ(t)> does not change its sign up to time t are studied in a one-dimensional directed percolation process by Monte Carlo simulations. At criticality, starting from random initial conditions, both P_l(t) and P_g(t) decay algebraically with exponents theta_l ~ theta_g ~ 1.50(2), which is in contrast to previously known cases where theta_g < theta_l. The exponents are found to be independent of the initial density and the microscopic details of the dynamics, suggesting that theta_l and theta_g are universal exponents. It is shown that in the special case of directed-bond percolation, P_l(t) can be related to a certain return probability of a directed percolation process with an active source (wet wall).

cond-mat.stat-mech↗

arXiv1997

A Model of Interface Growth with non-Burgers Dynamical Exponent

We define a new model of interface roughening which has the property that the minimum of interface height is conserved locally during the growth. This model corresponds to the limit $q \to \infty$ of the q-color dimer deposition-evaporation model introduced by us earlier [Hari Menon M K and Dhar D 1995 J. Phys. A: Math. Gen. 28 6517]. We present numerical evidence from Monte Carlo simulations and the exact diagonalization of the evolution operator on finite rings that this model is not in the universality class of the Kardar-Parisi-Zhang interface growth model. The dynamical exponent z in one dimension is larger than 2, with $z \approx 2.5$. And there are logarithmic corrections to the scaling of the gap with system size. Higher dimensional generalization of the model is briefly discussed.

cond-mat.stat-mech↗