International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

International Tables for Crystallography (2006). Vol. B, ch. 4.6, p. 488   | 1 | 2 |

Figure 4.6.2.1 

W. Steurera* and T. Haibacha

aLaboratory of Crystallography, Swiss Federal Institute of Technology, CH-8092 Zurich, Switzerland
Correspondence e-mail:  w.steurer@kristall.erdw.ethz.ch

[Figure 4.6.2.1]
Figure 4.6.2.1

The combination of a basic structure [s({\bf r})], with period a, and a sinusoidal modulation function [f(t)], with amplitude A, period λ and [t = {\bf q}\cdot {\bf r}], gives a modulated structure (MS) [s_{m}({\bf r})]. The MS is aperiodic if a and λ are on incommensurate length scales. The filled circles represent atoms.