How to control heat flow: a project from WUT's Faculty of Physics

Heat management is a critical issue for modern technologies. Overheating of electronic devices and energy losses in power systems limit their efficiency. Although we have long been able to control the flow of electric current, directional control of heat flow remains a scientific challenge. This issue is addressed by the project ‘Two-dimensional van der Waals heterostructures with asymmetric heat transport’, conducted at the Faculty of Physics of the Warsaw University of Technology under the leadership of Prof. Mariusz Zdrojek. The project partner is the Institute of Physics of the Polish Academy of Sciences.

As part of the research, the team plans to use materials engineering at the atomic scale to develop new methods of controlling heat flow. The aim of the project is to create nanodevices that will function as ‘one-way valves’. These will be constructed using two-dimensional materials, i.e. structures only a few atoms thick. These nanometre-thin layers, stacked like ultra-precise LEGO bricks, may revolutionise heat management in electronics, energy systems, and beyond.

The research will be based on van der Waals heterostructures, i.e. artificially designed stacks of different two-dimensional materials. These materials differ in their atomic lattice vibration properties. By carefully selecting and stacking the layers, it will be possible to create conditions in which heat flows more easily in one direction than in the other – a phenomenon known as the thermal diode effect, i.e., asymmetric heat flow.

Conceptual device structure: 2DM 1 – two-dimensional material type 1, 2DM 2 – two-dimensional material type 2

The researchers plan to combine materials containing heavier elements with lightweight materials such as graphene in order to enhance differences in atomic lattice vibrations. Advanced nanotechnology techniques will be used to construct the structures, including deterministic transfer and electron beam lithography, which enable the creation of highly precise interfaces between layers. The scientists will also rotate monolayers at specific angles and apply microscale strain to tune heat conduction.

The project also includes the construction of prototype nanoelectronic devices. First, quantum-mechanical simulations will be carried out to identify the most promising material configurations. Then, under high-purity conditions, structures equipped with microscopic heaters and sensors will be fabricated to enable the study of heat transport at a very small scale. The final stage will involve precise measurements of heat flow using Raman spectroscopy and electrical thermometry.

The expected outcomes include a prototype nanodevice that exhibits asymmetric heat flow, as well as the formulation of design principles for structures in which thermal properties can be tuned through the selection of materials, layer thickness, or twist angles. In the future, such solutions may support the design of more efficient electronic systems and new technologies for thermal energy management.

The project team consists of Prof. Mariusz Zdrojek, Arkadiusz Gertych, PhD, and Konrad Wilczyński, PhD. The research team also includes Leo Sagan, MSc, (PhD student) and Syed Hassan Abbas Jaffery, PhD, (postdoctoral researcher).