2.

(a) Schematic of the measured npn-type QD in the BLG/WSe₂ sample. (b) Finite-bias spectroscopy at the 0 h →1 h charge transition at zero magnetic field. The intersection of the excited state line with the Coulomb diamond edges (black dashed line) yields a spin–orbit gap of Δ_SO = 1.42 ± 0.02 meV. (c) Calculated evolution of quantum states in an in-plane magnetic field using the extracted Δ_SO. (d) Corresponding finite-bias measurement at B _∥ = 2 T. The excited-state energy (magenta dashed line) shows only a minor shift relative to the zero-field gap (black dashed line). (e) Calculated energy evolution in a perpendicular magnetic field using Δ_SO and g _v = 14, predicting the characteristic splitting of the two Kramers pairs. (f) Experimental finite-bias measurement at B _⊥ = 0.15 T, in agreement with the predicted splitting.