0_8597 Monolayer WTe₂ and MoTe₂ are topological semimetals with similar crystal symmetry and band structure close to Fermi energy. However, at low temperature the former material becomes an excitonic insulator [1,2] and the latter a superconductor, possibly of the unconventional kind [3]. Intriguingly, a tiny amount of electron doping is sufficient to turn WTe2 into a superconductor as well [4]. This suggests that collective electronic excitations, which are responsible for the excitonic instability in WTe2, might play a major role throughout the whole doping range. Here we investigate plasmons in doped WTe₂ and MoTe₂ using both first principles and model approaches. Instead of the - standard - search of the roots of the longitudinal dielectric function within the random phase approximation, we solve the Bethe-Salpeter equation of motion for collective modes. This allows to resolve the multicomponent nature of the plasmon, since both intra- and inter-band electron-hole excitations contribute to the mode, as well as to capture the texture of the wave function in reciprocal space. As shown by our preliminary results for WTe2, the plasmon presents qualitative deviations from the behavior expected in 2d systems [5]: the plasmon dispersion dramatically flattens close to Brillouin zone center and quickly merges the electron-hole continuum as momentum increases, the low mode energy being weakly sensitive to doping. This work is partially funded by MUR PRIN2017 No. 2017BZPKSZ “EXC-INS”. [1] Sun et al., Evidence for equilibrium exciton condensation in monolayer WTe₂. Nature Phys. 18, 94 (2022).[2] Jia et al., Evidence for a monolayer excitonic insulator. Nature Phys. 18, 87 (2022).[3] Rhodes et al., Enhanced superconductivity in monolayer Td-MoTe2. Nano Lett. 21, 2505 (2021).[4] Sajadi et al., Gate-induced superconductivity in a monolayer topological insulator. Science 362, 922 (2018).