Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

TL;DR

This paper introduces a nanoscale thermal imaging technique using a diamond-nanocrystal nitrogen-vacancy center on a silicon tip, enabling high-resolution heat flow mapping and dynamic temperature monitoring.

Contribution

The authors develop a novel scanning probe method combining NV centers with AFM to achieve nanoscale thermal conductivity imaging with fast response times.

Findings

Achieved nanoscale thermal conductivity maps with high spatial resolution.

Demonstrated real-time temperature monitoring during heat pulses.

Validated the technique with phantom microstructures.

Abstract

The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the NV to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. With the aid of a combined AFM/confocal setup, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps. The small mass and high thermal conductivity of the diamond host make the time response of our technique short, which we demonstrate by monitoring the tip temperature upon application of a heat pulse. Our approach promises multiple applications, from the investigation of phonon dynamics in nanostructures to the characterization of heterogeneous phase transitions and chemical reactions in various solid-state systems.