Broadband Microwave Spectroscopy for Two-Dimensional Material Systems

TL;DR

This paper introduces a simple broadband microwave spectroscopy technique tailored for micron-scale two-dimensional material flakes, enabling qualitative and quantitative analysis of their spectral features and complex conductivity.

Contribution

The paper presents a novel microwave spectroscopy method that overcomes size limitations of previous techniques for studying 2D materials.

Findings

The method can qualitatively detect spectral features.

It allows quantitative measurement of complex conductivity.

It does not require sophisticated sample preparation or Ohmic contacts.

Abstract

In recent years, interesting materials have emerged which are only available as micron-scale flakes, and whose novel physics might be better understood through broadband microwave spectroscopy; examples include twisted bilayer graphene [1], 2D materials in which many-body phases are observed [2], and artificial lattices for analog quantum simulations [3]. Most previous techniques are unfortunately not sensitive for flakes below mm lateral sizes. We propose a simple technique which does not require sophisticated sample preparation nor Ohmic contact and show through theory and simulations that one will be able to qualitatively measure spectral features of interest, and quantitatively measure the frequency-dependent complex conductivity.