In strongly correlated transition metal dichalcogenides, an intricate interplay of polaronic distortions, stacking arrangement, and electronic correlations determines the nature of the insulating state. Here, we study the response of the electronic structure to optical excitations to reveal the effect of chemical electron doping on this complex interplay. Transient changes in pristine and electron-doped 1T -TaS2 are measured by femtosecond time-resolved photoelectron spectroscopy and compared to theoretical modeling based on non-equilibrium dynamical mean-field theory and density functional theory. The fine changes in the oscillatory signal of the charge density wave amplitude mode indicate phase-dependent modifications in the Coulomb interaction and the hopping. Furthermore, we find an enhanced fraction of monolayers in the doped system. Our work demonstrates how the combination of time-resolved spectroscopy and advanced theoretical modeling provides insights into the physics of correlated transition metal dichalcogenides.
@article{arxiv.2504.19961,
title = {Ultrafast Electronic Structure Engineering in 1$T$-TaS$_2$: Role of Doping and Amplitude Mode Dynamics},
author = {J. Jayabalan and Jiyu Chen and Laura Pätzold and Francesco Petocchi and Florian K. Diekmann and Negar Najafianpour and Ping Zhou and Walter Schnelle and Gesa-R. Siemann and Philip Hofmann and Kai Roßnagel and Tim Wehling and Martin Eckstein and Philipp Werner and Uwe Bovensiepen},
journal= {arXiv preprint arXiv:2504.19961},
year = {2025}
}