Atomic resolution imaging at 2.5 GHz using near-field microwave microscopy

TL;DR

This paper demonstrates atomic resolution imaging at 2.5 GHz using a hybrid microwave-STM, revealing atomic-scale contrast through GHz frequency tunneling currents in a novel near-field microwave microscopy technique.

Contribution

The study introduces a hybrid microwave-STM that achieves atomic resolution imaging at GHz frequencies, combining tunneling and microwave resonator methods.

Findings

Atomic resolution images obtained at 2.5 GHz

Atomic contrast attributed to GHz frequency tunneling currents

Successful imaging of HOPG and Au(111) surfaces

Abstract

Atomic resolution imaging is demonstrated using a hybrid scanning tunneling/near-field microwave microscope (microwave-STM). The microwave channels of the microscope correspond to the resonant frequency and quality factor of a coaxial microwave resonator, which is built in to the STM scan head and coupled to the probe tip. We find that when the tip-sample distance is within the tunneling regime, we obtain atomic resolution images using the microwave channels of the microwave-STM. We attribute the atomic contrast in the microwave channels to GHz frequency current through the tip-sample tunnel junction. Images of the surfaces of HOPG and Au(111) are presented.