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arXiv 2101.01262cond-mat.mes-hall
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范德瓦尔斯异质结中间接激子的电压控制长程传输

Voltage-controlled long-range propagation of indirect excitons in van der Waals heterostructure

L. H. Fowler-Gerace, D. J. Choksy, L. V. Butov

摘要:

间接激子(IX),也称为层间激子,可以形成激子器件的介质,激子器件的操作基于激子的受控传播。激子器件的原理证明在GaAs异质结构中得到证明,其中激子器件的操作限于低温。范德华过渡金属二硫属化物(TMD)异质结构中的IX的特征在于高结合能,使得IX在室温下稳定,并提供了创建在高温下操作的适用于应用的激子器件的机会。然而,TMD异质结构的一个特征是存在莫尔超晶格势,这被预测会导致IX能量的调制达到数十meV。这些面内能量景观可以导致IX局部化,使得在TMD和GaAs异质结构中的IX传播根本不同,并且使得在TMD异质结构中是否可以实现长距离IX传播不确定。在这项工作中,我们实现了长距离IX传播的$1/e$ IX发光衰减距离达到13微米的MoSe $_2$ /WSe $_2$异质结构。实现了对激子发光的远程控制:激子晶体管漏极的激子发光信号被栅极电压控制在40倍以内。这些数据表明,长距离IX传播是可能的TMD异质结构与预测的莫尔超晶格势。

英文摘要:

Indirect excitons (IXs), also known as interlayer excitons, can form the medium for excitonic devices whose operation is based on controlled propagation of excitons. A proof of principle for excitonic devices was demonstrated in GaAs heterostructures where the operation of excitonic devices is limited to low temperatures. IXs in van der Waals transition-metal dichalcogenide (TMD) heterostructures are characterized by high binding energies making IXs robust at room temperature and offering an opportunity to create excitonic devices operating at high temperatures suitable for applications. However, a characteristic feature of TMD heterostructures is the presence of moiré superlattice potentials, which are predicted to cause modulations of IX energy reaching tens of meV. These in-plane energy landscapes can lead to IX localization, making IX propagation fundamentally different in TMD and GaAs heterostructures and making uncertain if long-range IX propagation can be realized in TMD heterostructures. In this work, we realize long-range IX propagation with the $1/e$ IX luminescence decay distances reaching 13 microns in a MoSe$_2$/WSe$_2$ heterostructure. We trace the IX luminescence along the IX propagation path. We also realize control of the long-range IX propagation: the IX luminescence signal in the drain of an excitonic transistor is controlled within 40 times by gate voltage. These data show that the long-range IX propagation is possible in TMD heterostructures with the predicted moiré superlattice potentials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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