Critical phenomena at perfect and non-perfect surfaces

TL;DR

This paper investigates how surface imperfections like randomness and steps affect critical phenomena in Ising models, finding that surface critical exponents remain largely unchanged.

Contribution

It provides a comparative Monte Carlo study of perfect and imperfect surfaces, revealing the robustness of surface critical exponents against various surface perturbations.

Findings

Surface critical exponents are robust against imperfections.

Monte Carlo simulations compare perfect and imperfect surfaces.

Surface steps and randomness do not significantly alter critical exponents.

Abstract

The effect of imperfections on surface critical properties is studied for Ising models with nearest-neighbour ferromagnetic couplings on simple cubic lattices. In particular, results of Monte Carlo simulations for flat, perfect surfaces are compared to those for flat surfaces with random, 'weak' or 'strong', interactions between neighbouring spins in the surface layer, and for surfaces with steps of monoatomic height. Surface critical exponents at the ordinary transition, in particular $\beta_1 = 0.80 \pm 0.01$, are found to be robust against these perturbations.