Table 1.

Harmonic susceptibilities of WSe₂ as a function of number of layers N.

Number of layers (N)	|χ(2)N| (10−19 m2 V−1)	|χ(3)N| (10−28 m3 V−2)
1	0.70 ± 0.09	0.9 ± 0.2
4	0.08 ± 0.08	3.4 ± 0.5
5	0.67 ± 0.09	4.5 ± 0.6
6	0.2 ± 0.1	6.0 ± 0.8
9	0.65 ± 0.08	8.6 ± 0.9
Average/sheet (per layer)	—	0.91 ± 0.07
	|χ(2)b| (10−10 m V−1)	|χ(3)b| (10−19 m2 V−2)
Bulk susceptibility	0.9 ± 0.1	1.16 ± 0.09

The reported values correspond to the mean ± standard deviation. The error values are obtained from the uncertainties of the relevant experimental parameters present in equations (1) and (2), through classical error propagation theory.