Table 2. Calculated Band Gaps (in eV) of the Studied MABX₃ Compounds for Different MA Orientations at Varying Levels of Approximation and Compared with the Available Experimental Data^a.

			calculated band gap (eV)
compounds	int. MA orient.	PBE	PBE+SOC	HSE	QSGW	QSGW+SOC	expt.
MAPbI3	[100]	1.55	0.47	1.99	2.47	1.79	1.55
	[110]	1.50	0.48
	[111]	1.45	0.44	1.95	2.40	1.65
MAPbBr3	[100]	1.93	0.84	2.51	3.13	2.55	2.30
	[110]	1.86	0.84
	[111]	1.80	0.70	2.43	3.01	2.28
MAPbCl3	[100]	2.41	1.30	3.10	3.91	3.49	2.90
	[110]	2.30	1.33
	[111]	2.31	1.23	3.04	3.80	3.33
MASnI3	[100]	0.50	0.10	1.29			1.20
	[110]	0.47	0.10
	[111]	0.49	0.10	1.26 (0.77)
MASnBr3	[100]	0.76	0.32	1.90			2.14
	[110]	0.76	0.38
	[111]	0.75	0.30	1.88
MASnCl3	[100]	1.83	1.46	3.10			3.6
	[110]	1.33	1.03
	[111]	1.49	1.06	2.94

^aNote: the HSE band gaps of Pb-based are obtained with 25% exact exchange, while the HSE band gaps of Sn-based are obtained with 55% exact exchange based on the experimental band gap of MASnI₃, and a number in parenthesis is obtained with 25% exact exchange.