The limits of near field immersion microwave microscopy evaluated by imaging bilayer graphene moiré patterns.

Ohlberg, Douglas A A; Tami, Diego; Gadelha, Andreij C; Neto, Eliel G S; Santana, Fabiano C; Miranda, Daniel; Avelino, Wellington; Watanabe, Kenji et al. · Nat Commun · 2021

basic_science · Level V

Where this comes from

Abstract

Near field scanning Microwave Impedance Microscopy can resolve structures as small as 1 nm using radiation with wavelengths of 0.1 m. Combining liquid immersion microscopy concepts with exquisite force control exerted on nanoscale water menisci, concentration of electromagnetic fields in nanometer-size regions was achieved. As a test material we use twisted bilayer graphene, because it provides a sample where the modulation of the moiré superstructure pattern can be systematically tuned from Ångstroms up to tens of nanometers. Here we demonstrate that a probe-to-pattern resolution of 108 can be obtained by analyzing and adjusting the tip-sample distance influence on the dynamics of water meniscus formation and stability.