Table 1. Effects of External Pressure P on the Electronic Band Gap and the Excitonic Responses^a.

P (GPa)	Eg (PBE/HSE06) (eV)	ΔEΓ (eV)	ExΓ–Γ (eV)	Exb (meV)	ExHb,1 (meV)
0	1.36/1.73	4.130	4.000	133.0	23.66
15	1.12/1.40	3.899	3.830	70.0	18.35
30	0.81/1.16	3.661	3.608	53.0	18.75
44	0.40/0.88	3.496	3.448	48.0	17.92
59	0.07/0.59	3.388	3.335	54.0	19.00
74	metal/0.40	3.327	3.272	55.0	18.49
88	metal/0.15	3.306	3.244	62.0	17.93
103	metal/0.02	3.316	3.243	73.0	17.32
118	metal/metal	3.354	3.261	93.0	20.19

^aHere, E_g denotes the electronic band gap obtained using PBE and HSE06 frameworks, ΔE_Γ denotes the HSE06-based Γ–Γ points energetic difference, Ex^Γ–Γ denotes the exciton state energy at the Γ point (MLWF-TB+BSE), Ex_b denotes the corresponding exciton binding energy (MLWF-TB+BSE) obtained by the difference of ΔE_Γ – Ex^Γ–Γ, and Ex^H_b,1 is the ground state exciton binding energy calculated from the hydrogenic model.