Fig. 1: Well-defined reciprocal length scale from real-space short-range order.
From: Establishing coherent momentum-space electronic states in locally ordered materials
a Fourier transforms for three real-space point distributions (crystalline, normal random, and disordered hard pack) demonstrates that reciprocal-space structure persists in the presence of well defined nearest-neighbor distance. b, c Large scale HRTEM image shows no signs of crystalline order like precursor lattice fringes. The electron diffraction pattern shows broad diffuse rings corresponding to SRO and no high intensity spots from long range order. d The reduced radial distribution function, G(r), has three peaks from a well defined nearest neighbor (2.4 Å), next nearest neighbor (3.5 Å), and third nearest neighbor (4.9 Å). e Coordination number for amorphous Bi2Se3 calculated using a 200 atom cell and ab-initio molecular dynamics, showing a peak at 6. Inset: an example coordination environment in amorphous Bi2Se3. f Ball-and-stick model of crystalline and amorphous Bi2Se3. For the amorphous structure, van der Waals separation is absent and majority sites are octahedral coordinated, implying an isotropic nearest neighbor distance.
