Researchers have made a groundbreaking discovery regarding the profound influence of microscopically localized defects on the thermal conduction of insulating materials. By harnessing the power of supercomputers and conducting extensive research on various crystalline substances, this finding has the potential to revolutionize the development of highly efficient nanoscale thermal insulators through defect engineering.
At the NOMAD Laboratory of the Fritz Haber Institute, scientists have shed light on the intricate microscopic mechanisms that dictate thermal conduction in heat insulators. Their computational investigations have revealed that even transient defect structures, limited in duration and microscopic in nature, wield a significant impact on macroscopic heat transport processes. This revelation opens up avenues for tailoring nanoscale thermal insulators through defect engineering, thereby paving the way for more energy-efficient technologies.
The recent breakthrough achieved by researchers at the NOMAD Laboratory elucidates fundamental microscopic mechanisms that hold the promise of customizing materials for superior heat insulation. This advancement represents a significant stride towards enhancing energy efficiency and sustainability.
The efficient transfer of heat plays a vital role in a range of scientific and industrial applications, including catalysis, turbine technologies, and thermoelectric heat converters that convert waste heat into electricity. In the context of energy conservation and the development of sustainable technologies, materials possessing exceptional thermal insulation capabilities are of utmost importance. These materials enable us to capture and harness heat that would otherwise dissipate. Consequently, improving the design of highly insulating materials remains a critical research objective in enabling more energy-efficient applications.
Image credit: © Florian Knoop, NOMAD Laboratory
However, designing robust heat insulators is far from a straightforward task, despite our understanding of the underlying fundamental physical laws for nearly a century. At the microscopic level, heat transport in semiconductors and insulators has been comprehended in terms of the collective oscillation of atoms around their equilibrium positions in the crystal lattice. These oscillations, commonly known as “phonons,” involve an immense number of atoms in solid materials, encompassing large, almost macroscopic length- and time-scales.
In a recent joint publication in Physical Review B (Editors Suggestions) and Physical Review Letters, researchers from the NOMAD Laboratory at the Fritz Haber Institute have pushed the boundaries of computational capabilities to calculate thermal conductivities with unparalleled accuracy, eliminating the need for experimental input. They demonstrated that the aforementioned phonon-based model is inadequate for strong heat insulators. By performing large-scale calculations on supercomputers at the Max Planck Society, the North-German Supercomputing Alliance, and the Jülich Supercomputing Centre, they examined over 465 crystalline materials, for which thermal conductivity measurements were not available. This study not only identified 28 highly efficient thermal insulators, six of which exhibited an ultra-low thermal conductivity comparable to that of wood but also shed light on previously overlooked mechanisms that facilitate systematic reduction of thermal conductivity.
“During our calculations, we observed the temporary formation of defect structures that exerted a massive influence on atomic motion, albeit for an extremely brief duration,” explained Dr. Florian Knoop (now affiliated with Linköping University), the first author of both publications. “Typically, such effects are disregarded in thermal-conductivity simulations due to the transient and microscopic nature of these defects compared to typical heat-transport scales, rendering them seemingly irrelevant. However, our calculations unequivocally demonstrated that they lead to decreased thermal conductivities,” added Dr. Christian Carbogno, a senior author of the studies.
These insights offer promising opportunities to finely tune and design thermal insulators at the nanoscale through defect engineering, thereby potentially contributing to advancements in energy-efficient technology.
“Anharmonicity in Thermal Insulators: An Analysis from First Principles” by Florian Knoop, Thomas A. R. Purcell, Matthias Scheffler, and Christian Carbogno, 7 June 2023, Physical Review Letters.
“Ab initio Green-Kubo simulations of heat transport in solids: Method and implementation” by Florian Knoop, Matthias Scheffler, and Christian Carbogno, 7 June 2023, Physical Review B.
Frequently Asked Questions (FAQs) about energy efficiency potential
What is the significance of the research on defects in thermal insulators?
The research on defects in thermal insulators is significant because it has revealed that microscopically localized defects have a substantial impact on thermal conduction. This finding opens up possibilities for designing more energy-efficient nanoscale thermal insulators through defect engineering.
What are the potential applications of this research?
The potential applications of this research are vast. It can contribute to the development of energy-efficient technologies in various fields such as catalysis, turbine technologies, and thermoelectric heat converters. It can also aid in enhancing energy conservation and sustainability efforts by improving the design of materials with high thermal insulation capabilities.
How does the research contribute to energy efficiency?
The research contributes to energy efficiency by uncovering mechanisms that allow for the systematic lowering of thermal conductivity in materials. By understanding the influence of defects on macroscopic heat transport processes, it provides insights for tailoring thermal insulators at the nanoscale level through defect engineering. This can lead to the development of more efficient energy conversion and utilization systems.
What computational methods were used in the research?
The researchers utilized supercomputers at the Max Planck Society, the North-German Supercomputing Alliance, and the Jülich Supercomputing Centre to conduct large-scale calculations. These computations enabled the scanning of over 465 crystalline materials to analyze their thermal conductivities without relying on experimental input, achieving unprecedented accuracy in thermal conductivity calculations.
How can this research contribute to sustainable technology?
This research can contribute to sustainable technology by enabling the design and development of more efficient thermal insulators. Highly insulating materials can help in capturing and utilizing heat that would otherwise go to waste, thereby improving energy efficiency. By leveraging defect engineering techniques based on the insights gained from this research, it becomes possible to create materials with enhanced thermal insulation capabilities, supporting the advancement of sustainable technologies.
More about energy efficiency potential
- “Anharmonicity in Thermal Insulators: An Analysis from First Principles” – Link to article
- “Ab initio Green-Kubo simulations of heat transport in solids: Method and implementation” – Link to article