Phonon-assisted electronic states modulation of few-layer PdSe2 at terahertz frequencies

Abstract Information technology demands high-speed optoelectronic devices, but going beyond the one terahertz (THz) barrier is challenging due to difficulties associated with generating, detecting, and processing high-frequency signals. Here, we show that femtosecond-laser-driven phonons can be utilized coherently manipulate excitonic properties of semiconductors at THz frequencies. The precise control pump subsequent time-delayed broadband probe pulses enables simultaneous generation detection processes both periodic lattice vibrations their couplings electronic states. Combining ultralow frequency Raman spectroscopy first-principles calculations, identify unique phonon mode-selective probe-energy dependent features electron–phonon interactions in layered PdSe 2 . Two distinctive types coherent excitations could couple preferentially different excitations: intralayer (4.3 THz) mode carriers interlayer (0.35 excitons. This work provides new insights understand excited-state 2D materials achieve future applications devices operating