Technical Review: Imaging weak magnetic field patterns on the nanometer-scale and its application to 2D materials

Abstract

Nanometer-scale imaging of magnetization and current density is the key to deciphering the mechanisms behind a variety of new and poorly understood condensed matter phenomena. The recently discovered correlated states hosted in atomically layered materials such as twisted bilayer graphene or van der Waals heterostructures are noteworthy examples. Manifestations of these states range from superconductivity, to highly insulating states, to magnetism. Their fragility and susceptibility to spatial inhomogeneities limits their macroscopic manifestation and complicates conventional transport or magnetization measurements, which integrate over an entire sample. In contrast, techniques for imaging weak magnetic field patterns with high spatial resolution overcome inhomogeneity by measuring the local fields produced by magnetization and current density. Already, such imaging techniques have shown the vulnerability of correlated states in twisted bilayer graphene to twist-angle disorder and revealed the complex current flows in quantum Hall edge states. Here, we review the state-of-the-art techniques most amenable to the investigation of such systems, because they combine the highest magnetic field sensitivity with the highest spatial resolution and are minimally invasive: magnetic force microscopy, scanning superconducting quantum interference device microscopy, and scanning nitrogen-vacancy center microscopy. We compare the capabilities of these techniques, their required operating conditions, and assess their suitability to different types of source contrast, in particular magnetization and current density. Finally, we focus on the prospects for improving each technique and speculate on its potential impact, especially in the rapidly growing field of two-dimensional (2D) materials.

24 pages, 4 figures, 3 boxes, 1 table

References in corpus (13)

• Highly confined low-loss plasmons in graphene-boron nitride heterostructures
• Scanning magnetic field microscope with a diamond single-spin sensor
• Probing magnetism in 2D materials at the nanoscale with single spin microscopy
• Single-spin magnetometry with multi-pulse sensing sequences
• Nano-engineered Diamond Waveguide as a Robust Bright Platform for Nanomagnetometry Using Shallow Nitrogen Vacancy Centers
• Magnetic domains and domain wall pinning in two-dimensional ferromagnets revealed by nanoscale imaging
• Imaging resonant dissipation from individual atomic defects in graphene
• Josephson junctions and SQUIDs created by focused helium ion beam irradiation of YBa${}_2$Cu${}_3$O${}_7$
• Long-range nontopological edge currents in charge-neutral graphene
• Co-existence of Bloch and Neel walls in a collinear antiferromagnet
• Characterization of room-temperature in-plane magnetization in thin flakes of CrTe${}_2$ with a single spin magnetometer
• Real-space imaging of quantum Hall effect edge strips
• Force sensing with nanowire cantilevers

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