1：Experimental Design and Method Selection:

A special load application unit was designed to be used with a standard laboratory Raman spectrometer, incorporating a transparent diamond indenter that functions as an optical objective. The method involves simultaneous indentation and Raman spectroscopy measurements.

2：Sample Selection and Data Sources:

A silicon sample with (100) surface orientation and thickness of about 0.4 mm was used, selected based on known phase transformations during indentation.

3：4 mm was used, selected based on known phase transformations during indentation. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes a linear translation stage with a stepper motor, resistive load cell, sample holder, housing, transparent diamond indenter (Berkovich pyramid shape), and a Raman spectrometer with a 20x objective (NA = 0.4). Materials include the silicon sample.

4：4). Materials include the silicon sample. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The sample was indented up to a maximum load of 50 N using the linear translator to push the sample into the fixed indenter. Raman spectra were collected at loads of 3 N, 10 N, 20 N, 30 N, 40 N, and 50 N during loading and unloading. The optical image was observed through the indenter, and spectra were measured directly through it.

5：Data Analysis Methods:

Raman peak shifts were analyzed to identify phases (e.g., Si-I, Si-II, Si-XII/Si-III) under different loads, using literature references for comparison and pressure estimation.