论文标题
极端紫外线瞬态吸收光谱中电荷密度波激发的电子和结构指纹
Electronic and structural fingerprints of charge density wave excitations in extreme ultraviolet transient absorption spectroscopy
论文作者
论文摘要
飞秒核心水平的瞬态吸收光谱用于研究Ti M2,3边缘（30-50 eV）在1T-TISE2中电荷密度波的光诱导动力学。发现光激发的载体和声子主要诱导核心水平激发的光谱红移，并且分别提取了大约360 FS和1.0 PS的载体弛豫时间和调子加热时间。将延迟依赖性吸收光谱中的明显振荡分配给光学$ A_ {1G} $ Phonon（6.0 THz）和$ A_ {1G}^*$电荷密度密度波幅度模式（3.3 THz）的相干激发。通过将测量光谱与时间依赖性密度函数理论模拟进行比较，我们确定了相干模式的瞬时原子位移的方向并估计它们的振幅。这项工作介绍了电荷密度波激发的首次浏览，并具有桌面核心水平的瞬态吸收光谱，从而可以同时访问电子和晶格激发和放松。
Femtosecond core-level transient absorption spectroscopy is utilized to investigate photoinduced dynamics of the charge density wave in 1T-TiSe2 at the Ti M2,3 edge (30-50 eV). Photoexcited carriers and phonons are found to primarily induce spectral red-shifts of core-level excitations, and a carrier relaxation time and phonon heating time of approximately 360 fs and 1.0 ps are extracted, respectively. Pronounced oscillations in delay-dependent absorption spectra are assigned to coherent excitations of the optical $A_{1g}$ phonon (6.0 THz) and the $A_{1g}^*$ charge density wave amplitude mode (3.3 THz). By comparing the measured spectra with time-dependent density functional theory simulations, we determine the directions of the momentary atomic displacements of both coherent modes and estimate their amplitudes. This work presents a first look on charge density wave excitations with table-top core-level transient absorption spectroscopy, enabling simultaneous access to electronic and lattice excitation and relaxation.
