1：Experimental Design and Method Selection:

The study employed neutron diffraction (ND), X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS) measurements at the Ge, Ga, and Sb K-edges. The reverse Monte Carlo (RMC) simulation technique was used to fit the experimental data sets simultaneously.

2：Sample Selection and Data Sources:

Samples were prepared by conventional melt quenching using high purity raw materials. The densities of the samples were determined using a Mettler Toledo XS64 system.

3：List of Experimental Equipment and Materials:

Neutron diffraction experiments were carried out at the 7C2 diffractometer of LLB (Saclay, France). XRD structure factors were measured at the beamline P07 of the Petra III source (Hamburg, Germany). EXAFS measurements at the Ge, Ga, and Sb K-edges were carried out at HASYLAB (beamline X).

4：Experimental Procedures and Operational Workflow:

Powdered samples were filled into thin walled vanadium containers for ND experiments. Corrected ND and XRD structure factors were obtained by integrating 2D counts and correcting for background, absorption, detector efficiency, and multiple scattering.

5：Data Analysis Methods:

The experimental data sets were fitted simultaneously by the RMC++ code. The EXAFS backscattering coefficients were calculated by the FEFF8.4 program.