Phonon-assisted electronic states modulation of few-layer PdSe2 at terahertz frequencies
Phonon-assisted electronic states modulation of few-layer PdSe2 at terahertz frequencies
复制标题
太赫兹频率下少层 PdSe2 的声子辅助电子态调制
DOI：
10.1038/s41699-021-00268-3
复制
发表时间：
2021-11-26
影响因子：
9.7
通讯作者：
Chen, Feng
中科院分区：
文献类型：
--
作者：
Li, Ziqi;Peng, Bo;Chen, Feng
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.
