Local Measurement of Microwave Response with Local Tunneling Spectra Using Near Field Microwave Microscopy

TL;DR

This paper presents a near-field microwave microscope capable of measuring local microwave response and density-of-states variations at 7.3 GHz, revealing differences in surface resistance between gold-deposited and non-deposited regions on graphite.

Contribution

The study introduces a novel near-field microwave microscopy technique for spatially resolving local microwave response and LDOS at GHz frequencies.

Findings

Surface resistance is lower in gold-deposited regions.

LDOS varies across the boundary between gold and graphite.

Microscopy reveals spatial variation in microwave response.

Abstract

We have designed and built a near-field scanning microwave microscope, which has been used to measure the local microwave response and the local density-of-states (LDOS) in the area including the boundary between the gold deposited and the non-deposited region on highly-orientated pyrolytic graphite at a frequency of about 7.3 GHz. We have succeeded in measuring the spatial variation of both the LDOS and the surface resistance. It can be observed that the surface resistance in gold deposited region with the metallic tunneling spectra is smaller than that in the non-deposited region with the U-shaped tunneling spectra.