论文标题
莫特绝缘电荷密度波状态的光发射1T-TAS2的光发射光谱的相分辨频域分析
Phase-resolved frequency-domain analysis of the photoemission spectra for photoexcited 1T-TaS2 in the Mott insulating charge density wave state
论文作者
论文摘要
我们通过时间和角度分辨光发射光谱法研究了1T-TAS2的非平衡电子结构。我们观察到强烈的光激发会引起莫特间隙的崩溃，从而导致光诱导的金属相。还发现，光发射强度的振荡是由于对应于电荷密度波（CDW）的振幅模式的相干声子激发的结果。为了研究通过CDW振幅模式调制的带分散的动力变化，我们通过使用频域角度分辨光发射光谱（FDARPES）进行分析。我们发现，两个不同的峰结构通过检索FDARPES光谱的振幅和相位部分相对于彼此表现出反相振荡。它们归因于能量中的最小和最大频带位置，其中单个频段与CDW振幅模式同步之间振荡。我们进一步发现，由于CDW带折叠的结果，在振荡期间构建的扁平带存活了，而Mott GAP显着降低了。我们的结果表明CDW相是稳健的，与CDW振幅模式相对应的晶格调制会动态调节Mott GAP。
We investigate the nonequilibrium electronic structure of 1T-TaS2 by time- and angle-resolved photoemission spectroscopy. We observe that strong photoexcitation induces the collapse of the Mott gap, leading to the photo-induced metallic phase. It is also found that the oscillation of photoemission intensity occurs as a result of the excitations of coherent phonons corresponding to the amplitude mode of the charge density wave (CDW). To study the dynamical change of the band dispersions modulated by the CDW amplitude mode, we perform analyses by using frequency-domain angle-resolved photoemission spectroscopy (FDARPES). We find that two different peak structures exhibit anti-phase oscillation with respect to each other by retrieving the amplitude and phase parts of the FDARPES spectra. They are attributed to the minimum and maximum band positions in energy, where the single band is oscillating between them synchronizing with the CDW amplitude mode. We further find that the flat band constructed as a result of CDW band folding survives during the oscillation while the Mott gap is significantly reduced. Our results suggest the CDW phase is robust, and the lattice modulation corresponding to the CDW amplitude mode dynamically modulates the Mott gap.
