Deep subwavelength control of valley polarized cathodoluminescence in h-BN/WSe2/h-BN heterostructure

Valley pseudospin in transition metal dichalcogenides monolayers intrinsically provides additional possibility to control valley carriers, raising a great impact on valleytronics in following years. The spin-valley locking directly contributes to optical selection rules which allow for valley-dependent addressability of excitons by helical optical pumping. As a binary photonic addressable route, manipulation of valley polarization states is indispensable while effective control methods at deep-subwavelength scale are still limited. Here, we report the excitation and control of valley polarization in h-BN/WSe2/h-BN and Au nanoantenna hybrid structure by electron beam. Near-field circularly polarized dipole modes can be excited via precise stimulation and generate the valley polarized cathodoluminescence via near-field interaction. Effective manipulation of valley polarization degree can be realized by variation of excitation position. This report provides a near-field excitation methodology of valley polarization, which offers exciting opportunities for deep-subwavelength valleytronics investigation, optoelectronic circuits integration and future quantum information technologies.

Automated summary

The valley pseudospin in transition metal dichalcogenides monolayers offers additional possibilities for controlling valley carriers, impacting valleytronics significantly. By exciting and controlling valley polarization, effective manipulation of the degree of valley polarization can be achieved. This method provides exciting opportunities for deep-subwavelength valleytronics research and optoelectronic circuit integration.