Subcycle contact-free nanoscopy of ultrafast interlayer transport in atomically thin heterostructures

Tunnelling is one of the most fundamental manifestations quantum mechanics. The recent advent lightwave-driven scanning tunnelling microscopy has revolutionized ultrafast nanoscience by directly resolving electron in electrically conducting samples on relevant ultrashort length- and timescales. Here, we introduce a complementary approach based terahertz near-field to perform nano-videography processes even insulators. central idea probe evolution local polarizability electron–hole pairs with evanescent fields, which detect subcycle temporal resolution. In proof concept, resolve femtosecond interlayer transport van der Waals heterobilayers reveal pronounced variations formation annihilation excitons deeply subwavelength, nanometre scales. Such contact-free nanoscopy tunnelling-induced dynamics should be universally applicable non-conducting how shape functionalities wide range condensed matter systems. Subcycle charge-transfer WSe2/WS2 heterostructures obtained using microscopy. fields.