X-ray scattering from semiconductors and other materials
in which f is the force per unit length at a point on a dislocation line, σ is the local stress field, b is the Burgers vector and ξ is the local line tangent direction, so the PK force is always perpendicular to the line itself. I would have liked to have seen more explanation of this equation in the Introduction, bearing in mind that σ is a second-rank tensor and the other entities are vectors; and that it is needed again in Chapter 10. I would have also liked to have seen more pictures of dislocation arrays (either electron micrographs or X-ray topographs) and some experimental results, against which the success of the computer simulations could have been judged. Although the final section (11.6) contrasts the PFM with the line DD technique, the book lacks a comprehensive conclusion. This could have summarized and compared the relative merits, computation times and applicability of all the simulation techniques employed. As is noted in Section 7.1, molecular dynamics simulations have an integration step of order one femtosecond (10−15 s), so the time horizon is unlikely to exceed one nanosecond (10−9 s). Dislocation behaviours of interest however occur on timescales of milliseconds (10−3 s) or longer. The authors have written fluently and scholarly; and they have supplied informative introductory paragraphs to each chapter and summaries of the main points at the end of each section. I did not find any typographical errors. Numerous acronyms are used, including those given above, such as CGR, CSD, DFT, EAM, EMT, FMM, kMC, MC, MEP, NEB, PBC, SA, SW, TAS, TB, TST. A list of all of these, with their definitions, would be a helpful reference for the reader. The meanings of some letters in equations are not clear: for example, the ‘fictitious parameter’ ζ (t) in the Nose–Hoover Thermostat (Section 4.4.2). There are many problems (of some difficulty) set for the reader/student, but there are no answers or solutions within the book. There are however helpful hints and useful links to computer programs and codes in the website. Bearing in mind that materials modelling is a recent and rapidly expanding research area, it would be good if the authors could be persuaded to include in the website the salient updates in the decade beyond the original publication date of 2006, ready for the next edition.