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 the difficulties associated with generating, detecting, and processing high-frequency signals. Here, we show that femtosecond-laser-driven phonons can be utilized to coherently manipulate the excitonic properties of semiconductors at THz frequencies. The precise control of the pump and subsequent time-delayed broadband probe pulses enables the simultaneous generation and detection processes of both periodic lattice vibrations and their couplings with electronic states. Combining ultralow frequency Raman spectroscopy with first-principles calculations, we identify the unique phonon mode-selective and probe-energy dependent features of electron-phonon interactions in layered PdSe2. Two distinctive types of coherent phonon excitations could couple preferentially to different types of electronic excitations: the intralayer (4.3 THz) mode to carriers and the interlayer (0.35 THz) mode to excitons. This work provides new insights to understand the excited-state phonon interactions of 2D materials, and to achieve future applications of optoelectronic devices operating at THz frequencies.

References in corpus (9)

• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Quasiparticle band structure based on a generalized Kohn-Sham scheme
• Ultrafast Electron-Phonon Decoupling in Graphite
• Large, valley-exclusive Bloch-Siegert shift in monolayer WS2
• Direct Determination of Band Gap Renormalization in Photo-Excited Monolayer MoS2
• Strongly coupled coherent phonons in single-layer MoS${}_2$
• Mode-resolved reciprocal space mapping of electron-phonon interaction in the Weyl semimetal candidate Td-WTe${}_2$
• Direct measurement of electron-phonon coupling with time-resolved ARPES
• Light-induced renormalization of the Dirac quasiparticles in the nodal-line semimetal ZrSiSe

Cited by in corpus (2)

• Monolayer fullerene networks as photocatalysts for overall water splitting
• Multi-gap topology and non-Abelian braiding of phonons from first principles