Fig. 3. Valley phonon replicas of negatively charged dark trion.

a Circular polarization resolved PL of the triplet PL peaks under electron-doped conditions. The photon energy of the spectrum is offset with respect to the negatively charged dark trion (D⁻). b Magneto PL of the triplets with σ⁻ excitation and co-polarized detection. The photon energy of the spectrum is offset with respect to D⁻ at zero field. c Gate-dependent PL with σ⁺ resonant pumping of the bright exciton and cross polarized (σ⁻) detection. The $D_{K_1}^{-}$ state on the electron doping side, which is 18 meV below D⁻, is clearly resolved. d Magneto PL at the gate voltage indicated by the orange arrow in c, with σ⁺ excitation and σ⁻detection.