Don’t Trust your Simulation -Computational Materials Science on its Way to Maturity?

Abstract

A Model is a Model is a ModelThe title of this article is of course meant to provoke. Why? Because a menace of confusing models with reality always exists. Does anyone nowadays refer to ªfirst principles simulationsº? This point is well taken. However, practically all of the current predictions in this domain are based on simulating electron dynamics using local density functional theory. These simulations, though providing a deep insight into materials ground states, are not exact but approximate solutions of the Schrödinger equation, whichÐwe should not forgetÐis a model itself. [1] Does anyone still refer to ªfinite-element simulationsº? This point is also well taken. However, also in this case one has to admit that approximate solutions to large sets of nonlinear differential equations formulated for a (non-existing) continuum under idealized boundary conditions is what it is: a model of nature but not reality.But let us calm down and render the discussion a bit more seriousness: current methods of ground-state calculations are definitely among the cutting-edge disciplines in computational materials science and the community has learnt much from it during the last years. Similar aspects apply for some continuum-based finite-element simulations. After all, this article is meant to attract readers into this exciting field and not to repulse them. And for this reason I feel obliged to first make a point in underscoring that any interpretation of a research result obtained by computer simulation should be ac-companied by scrutinizing the model ingredients and boundary conditions of that calculation in the same critical way as an experimentalist would check his experimental set-up.In the following I will address some important aspects of computational materials science. The selection is of course biased (more structural than functional; more metals than non-metals; more mesoscale than atomic scale). I will try to reach a balance between fundamental and applied topics. The article focuses particularly on topics and publications of 2001 and 2002. Some Semantics of Modeling and SimulationBefore continuing in medias res, let us revisit some basic thoughts on the semantics of modeling and simulation. The words modeling and simulation are often distinguished by somewhat arbitrary arguments or they are simply used synonymously. This lack of clarity reflects that concepts in computational materials science develop faster than semantics. To establish a common language in this field, a less ambiguous ADVANCED ENGINEERING MATERIALS 2002, 4, No. 5 255 ± [*] Prof.Progress reports are a new type of article in Advanced Engineering Materials, dealing with the hottest current topics, and providing readers with a critically selected overview of important progress in these fields. It is not intended that the articles be comprehensive, but rather insightful, selective, critical, opinionated, and even visionary. We have approached scientists we believe are at the very forefront of these fields to contribute the articles, which will ap...