Source: U.S. Army Research Laboratory
In the world of innovation, controlling heat flow at the nanoscale has long been considered one of the most challenging topics in scientific research. Today, researchers at the University of Michigan — funded by the U.S. Army Research Laboratory — have achieved a major breakthrough in this field. They have developed nanoscale thermal switches — devices that may play a crucial role in the future in:
• thermal management of nanoscale devices,
• highly efficient cooling systems,
• thermal-based data storage technologies,
• thermal computing,
• and intelligent building temperature regulation.
This discovery is particularly significant because controlling heat flow at nanoscale dimensions was previously regarded as an almost impossible task.
For the first time, thermal switching at the nanoscale has been demonstrated
The study, published in Nature Nanotechnology, shows for the first time that heat transfer between two nanometer-thick membranes can be controlled through the activation of specific nanoscale effects.
While there is a wide range of devices that regulate electrical current — such as transistors and diodes — there are very few analogous functional components for controlling heat flow, especially at the nanoscale. This limitation has pushed researchers to explore new physical phenomena.
Dr. Chakrapani Varanasi, program manager at the U.S. Army Research Laboratory, commented:
“It is extremely important that the Army invests in fundamental research like this. These findings could strongly influence next-generation military computing and thermal management systems.”
This work is also part of the U.S. Army’s network modernization strategy — aimed not only at strengthening current technologies but also at developing next-generation solutions that outperform potential adversaries.
The beginning of the discovery — the 2018 study
One of the lead authors, Dr. Dakotah Thompson, continued the work of a 2018 study in which the research group demonstrated how heat behaves differently depending on direction when passing through nanomembranes. Building on that foundation, Thompson began exploring more practical applications of these effects.
He proposed the following hypothesis:
the thermal emission of nanomembranes can be modified by placing a third object near them, enabling a switchable thermal transition.
Professor of Mechanical Engineering at the University of Michigan, Dr. Edgar Meyhofer, played a critical role in designing the specific experimental setup needed to test this idea.
A unique experiment — controlling heat flow between two membranes
During the research, Thompson developed high-precision suspended calorimetric devices and added a third nanostructure — a “planar mesa” — to the system. Using an ultra-precise nanopositioner, he adjusted the distance between the membranes with nanometer-scale accuracy.
These experiments showed that:
heat transfer between the membranes can be turned on and off simply by changing the distance between them.
This is the first real experimental evidence supporting the concept of a nanoscale “thermal switch.”
Numerical modeling and accuracy of findings
The study’s authors — Dr. Linxiao Zhu and Dr. Thompson — carried out extensive numerical calculations to explain the observations with high precision.
They found that:
• the heat transfer between the membranes occurs primarily through controllable electromagnetic radiation,
• the third object (planar mesa) can either enhance or suppress this radiative coupling,
• thus, heat flow at the nanoscale can effectively be “switched on” and “switched off.”
Conclusion: a major step toward the thermal technologies of the future
This research contributes significantly not only to fundamental science but also to the advancement of practical applications. Nanoscale thermal switches may become key components in:
• ultra-fast computers,
• thermal-based data storage systems,
• energy-efficient smart buildings,
• advanced military technologies,
• nanorobotics and microsystem engineering.
By making precise control of heat flow possible, this breakthrough opens a new chapter in the technological future, paving the way for next-generation energy and computing solutions.