ISIS Neutron and Muon Source Data Journal

Phonon dispersion curves and First and second order displacements in a Disordered Si-rich Si-Ge Alloy.

Abstract: Silicon germanium alloys are key materials for high-performance electronic and optoelectronic devices such as field-effect transistors, quantum cascade lasers, and heterojunction bipolar transistors. The intrinsic atomic size difference between Si and Ge induces local lattice distortions and long-range strain fields that influence phonon dynamics, defect formation, and carrier transport. Neutron scattering provides a unique means to probe both static and dynamic lattice responses in such disordered systems. Diffuse scattering measurements are sensitive to atomic displacements and strain fields, producing characteristic Huang and size-effect scattering. Inelastic neutron scattering complements this by mapping phonon dispersion and revealing Ge-Ge resonance modes affected by local strain and mass disorder. Preliminary measurements confirmed strain-related diffuse scattering in Si0.9Ge0.1, but limited Q-range coverage prevented the precise extraction of SRO and SE parameters. We propose extended measurements with 50% greater reciprocal-space coverage using a 2.3 g sample crystal. Room-temperature data will provide phonon dispersion and Ge Ge resonance modes, while low-temperature measurements will isolate the elastic line. With time-of-flight analysis and absolute normalization using a vanadium standard, these experiments will yield quantitative SRO and SE displacement parameters, advancing understanding of static strain and phonon coupling in Si-rich SiGe alloys.

Principal Investigator: Dr Jose Abelardo Rodriguez Rivera
Local Contact: Dr Viviane Pecanha Antonio
Experimenter: Dr Chris Stock

DOI: 10.5286/ISIS.E.RB2610223

ISIS Experiment Number: RB2610223

Publisher: STFC ISIS Neutron and Muon Source

Data format: RAW/Nexus
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Data Citation

The recommended format for citing this dataset in a research publication is as:
[author], [date], [title], [publisher], [doi]

For Example:
Dr Jose Abelardo Rodriguez Rivera et al; (2026): Phonon dispersion curves and First and second order displacements in a Disordered Si-rich Si-Ge Alloy., STFC ISIS Neutron and Muon Source, https://doi.org/10.5286/ISIS.E.RB2610223

Data is released under the CC-BY-4.0 license.