A Model for Growth of Binary Alloys with Fast Surface Equilibration

TL;DR

This paper introduces a growth model for binary alloy films where surface atoms equilibrate rapidly while bulk atoms are frozen, revealing anisotropic correlations and critical behavior near phase transitions.

Contribution

It presents a novel model capturing the anisotropic growth and surface equilibration effects in binary alloy films, linking surface dynamics to bulk properties.

Findings

Correlations perpendicular to growth are like a d-dimensional two-layer system.

In-plane correlations depend on Glauber dynamics and interactions.

Near critical points, correlation volumes change shape and critical exponents vary continuously.

Abstract

We study a simple growth model for (d+1)-dimensional films of binary alloys in which atoms are allowed to interact and equilibrate at the surface, but are frozen in the bulk. The resulting crystal is highly anisotropic: Correlations perpendicular to the growth direction are identical to a d-dimensional two-layer system in equilibrium, while parallel correlations generally reflect the (Glauber) dynamics of such a system. For stronger in-plane interactions, the correlation volumes change from oblate to highly prolate shapes near a critical demixing or ordering transition. In d=1, the critical exponent z relating the scaling of the two correlation lengths varies continuously with the chemical interactions.