Quantum imaging of current flow in graphene.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Technology

Background:

• Graphene exhibits unique electronic transport phenomena crucial for advanced devices.
• Traditional resistivity measurements lack spatial information vital for studying these phenomena.
• Understanding current flow in real-space is essential for characterizing graphene devices.

Purpose of the Study:

• To develop and demonstrate a noninvasive quantum imaging technique for visualizing current flow in graphene.
• To achieve high-resolution mapping of current density in various graphene structures.
• To investigate the impact of nanoscale defects on electronic transport in graphene.

Main Methods:

• Utilized an engineered array of atomic-sized quantum sensors in diamond.
• Mapped the vector magnetic field generated by current flow in graphene.
• Reconstructed the vector current density with submicrometer spatial resolution.

Main Results:

• Successfully imaged current flow in monolayer graphene, including monoribbons and junctions.
• Achieved spatial resolution at the diffraction limit.
• Detected strong spatial variations in current corresponding to physical defects at the submicrometer scale.
• Demonstrated projected sensitivity to currents as small as 1 μA.

Conclusions:

• Quantum imaging provides a powerful new tool for noninvasive, high-resolution analysis of electronic transport in graphene.
• The method reveals nanoscale defects influencing current flow, critical for device performance.
• This technique has broad applicability for studying emerging two-dimensional materials and thin-film systems.