Optical read-out of Coulomb staircases in a moiré superlattice via trapped interlayer trions.
Optical read-out of Coulomb staircases in a moiré superlattice via trapped interlayer trions.
复制标题
DOI：
10.1038/s41565-021-00970-9
复制
发表时间：
2021-11
影响因子：
38.3
通讯作者：
Gerardot BD
中科院分区：
文献类型：
--
作者：
Baek H;Brotons-Gisbert M;Campbell A;Vitale V;Lischner J;Watanabe K;Taniguchi T;Gerardot BD
具有超晶格势的莫尔图案可以通过垂直堆叠具有相对扭曲或晶格常数失配的两层材料来形成。在基于过渡金属二硫属化物的系统中，莫尔势景观可以在特定的原子登记处捕获层间激子（IX）。在这里，我们报告说，空间隔离的被困IX在钼二硒化物/钨二硒化物异质双层器件提供了一个敏感的光学探针的载体填充在其直接的环境。通过绘制单个被捕获IX的空间位置，我们能够在莫尔晶格充满多余载流子时光谱跟踪发射器。在异质双层的初始掺杂时，中性捕获的IX形成均匀带电的IX（IX trions），其结合能为~7 meV。在进一步掺杂时，空的超晶格位点依次填充，产生库仑阶梯：由于库仑与最近邻摩尔位点处的载流子相互作用，IX三电子发射能量逐步变化。这种非侵入性、高度局部化的技术可以补充传输和非局部光学传感技术，以表征库仑相互作用能、可视化电荷相关态或探测莫尔超晶格中的局部无序。在过渡金属二硫属化物异质双层膜中，莫尔陷阱层间激子作为载流子在其直接环境中填充的灵敏光学探针来表征莫尔超晶格的掺杂。
Moiré patterns with a superlattice potential can be formed by vertically stacking two layered materials with a relative twist or lattice constant mismatch. In transition metal dichalcogenide-based systems, the moiré potential landscape can trap interlayer excitons (IXs) at specific atomic registries. Here, we report that spatially isolated trapped IXs in a molybdenum diselenide/tungsten diselenide heterobilayer device provide a sensitive optical probe of carrier filling in their immediate environment. By mapping the spatial positions of individual trapped IXs, we are able to spectrally track the emitters as the moiré lattice is filled with excess carriers. Upon initial doping of the heterobilayer, neutral trapped IXs form charged IXs (IX trions) uniformly with a binding energy of ~7 meV. Upon further doping, the empty superlattice sites sequentially fill, creating a Coulomb staircase: stepwise changes in the IX trion emission energy due to Coulomb interactions with carriers at nearest-neighbour moiré sites. This non-invasive, highly local technique can complement transport and non-local optical sensing techniques to characterize Coulomb interaction energies, visualize charge correlated states, or probe local disorder in a moiré superlattice. Moiré-trapped interlayer excitons in a transition metal dichalcogenide heterobilayer serve as a sensitive optical probe of carrier filling in their immediate environment to characterize the doping of the moiré superlattice.
登录
查看更多内容
影响因子：
16.6
作者：
Branny A;Kumar S;Proux R;Gerardot BD
通讯作者：
Gerardot BD
影响因子：
38.3
作者：
Sung, Jiho;Zhou, You;Park, Hongkun
通讯作者：
Park, Hongkun
影响因子：
1.6
作者：
BOBROFF, N
通讯作者：
BOBROFF, N
影响因子：
64.8
作者：
Regan, Emma C.;Wang, Danqing;Wang, Feng
通讯作者：
Wang, Feng
影响因子：
64.8
作者：
Seyler, Kyle L.;Rivera, Pasqual;Xu, Xiaodong
通讯作者：
Xu, Xiaodong