Direct Structure Determination of Systems with Two Dimensional Periodicity

We demonstrate a new general x-ray method for the direct determination of the structure of materials which are periodic in the two dimensions and aperiodic in the third (2D crystals), encompassing many systems of scientific and technological interest. The structure is obtained from the amplitude and phase of the complex structure factor and its subsequent three-dimensional back Fourier transformation into real space. The method is illustrated with experimental and simulated data, showing that the structure can be determined with atomic resolution.