Polarization switching and electrical control of interlayer excitons in two-dimensional van der Waals heterostructures

• DOI: 10.1038/s41566-018-0325-y
• Publication Date: 2018-12-13T16:37:34Z
• Authors: Alberto Ciarrocchi; Dmitrii Unuchek; Ahmet Avsar; Kenji Watanabe; Takashi Taniguchi; Andras Kis
• Keywords: Condensed Matter - Mesoscale and Nanoscale Physics; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); FOS: Physical sciences; 02 engineering and technology; 0210 nano-technology; Article

Long-lived interlayer excitons with distinct spin-valley physics in van der Waals heterostructures based on transition metal dichalcogenides make them promising for information processing in next-generation devices. While the emission characteristics of interlayer excitons in different types of hetero stacks have been extensively studied, the manipulation of these excitons required to alter the valley-state or tune the emission energy and intensity is still lacking. Here, we demonstrate such control over interlayer excitons in MoSe2/WSe2 heterostructures. The encapsulation of our stack with h-BN ensures ultraclean interfaces, allowing us to resolve four separate narrow interlayer emission peaks. We observe two main interlayer transitions with opposite helicities under circularly polarized excitation, either conserving or inverting the polarization of incoming light. We further demonstrate control over the wavelength, intensity, and polarization of exciton emission by electrical and magnetic fields. Such ability to manipulate the interlayer excitons and their polarization could pave the way for novel excitonic and valleytronic device applications.