Computational Study of Strong Phonon Softening and Electron–Phonon Interaction in Doped Monolayer Tellurene: Implications for Neuromorphic Applications

Synthesized two-dimensional tellurene (2D-Te) has gained widespread attention due to its merits of air stability and high carrier mobility. However, the mechanism of intrinsic carrier-lattice scattering, governing the transport performance of 2D-Te is still unknown. Herein, the doped α phase of 2D-Te is explored with respect to its intrinsic electron–phonon (e-p) coupling mechanism via density functional theory and Wannier interpolation methods. We reveal that electron doping can strongly renormalize the phonon of 2D-Te, while hole doping leads to instability. Substantial softening in phonons occur with electron doping in pristine monolayer tellurene, and in particular, dipping initiates in dispersion around the zone center and midst of M-K high-symmetry points. Especially, when electron doping coexists with strains, the lattice suffers from undulation and exhibits poor stability behavior. The occurrence of enhanced softening of those phonons coincides with enhanced e-p scattering and is rooted in the pocket states generated by the upward-shifted Fermi level. The asymmetric dependence of doping polarity and the selectively enhanced softening behavior with tunable lattice-charge coupling make 2D-Te a unique system for reconfigurational operation and neuromorphic applications.