AI 中文总结
本研究在R型WSe₂/WS₂双层结构中，探究宽范围IX和电荷密度下的IX PL寿命与谷极化，发现电荷不可压缩相极化下降源于IX寿命提升的稀释效应，还观测到IXX的反常谷极化，揭示莫尔异质双层多体物理对IX动力学的调控。
AI 中文摘要
莫尔过渡金属二硫化物异质结构中的局域层间激子（IX）既能探测莫尔超晶格所承载的多体态，也能参与其中。当IX密度远小于莫尔晶格密度时，分数电子莫尔填充处不可压缩电荷晶体的形成会改变激子-电荷散射，导致光致发光（PL）测量中的寿命延长。在高IX密度下，激子动力学因激子莫特绝缘体的出现和双占据位点（IXX）的形成而改变。本研究在宽范围的IX和电荷密度下，探究R型WSe₂/WS₂双层结构中的IX PL寿命和谷极化。过往研究报道，电荷不可压缩相的时间积分测量中极化会下降，而本研究表明，这并非源于谷间散射增强，而是IX寿命显著提升导致谷极化被稀释。在高激发密度下，探究IXX的动力学，结果显示，尽管两个组成激子具有名义上的反平行谷构型，但IXX布居衰减时会出现强烈的反常谷极化。研究结果揭示了IX复杂的激子和谷动力学，证明其受莫尔异质双层丰富的多体物理强烈调控。
英文摘要
Localized interlayer excitons (IX) in moiré transition metal dichalcogenide heterostructures can both probe and participate in many-body states hosted by the moiré superlattice. When the IX density is small compared to the moiré lattice density, the formation of incompressible charge crystals at fractional electronic moiré fillings modifies exciton-charge scattering, leading to enhanced lifetimes in photoluminescence (PL) measurements. At high IX densities, the exciton dynamics are altered by the emergence of an excitonic Mott insulator and the formation of doubly-occupied sites (IXX). Here, we investigate the IX PL lifetime and valley polarization in an R-type $\mathrm{WSe_2}$/$\mathrm{WS_2}$ bilayer across a wide range of IX and charge densities. While previous studies reported a decrease of polarization in time-integrated measurements in charge-incompressible phases, our results show that this arises not from enhanced intervalley scattering, but from a dilution of the valley polarization by the dramatic enhancement of IX lifetimes. At high excitation densities, we probe the dynamics of the IXX and show that despite the nominal antiparallel valley configuration of the two constituent excitons, a strong, anomalous valley polarization develops as the IXX population decays. Our results shed light on the complex exciton and valley dynamics of IX and demonstrate that they are strongly modified by the rich many-body physics of moiré heterobilayers.
Comments12 pages, 4 figures. Extended Data: 4 figures
