Diamond, well known as a precious gemstone, also has numerous remarkable physical properties that make it important in industrial applications. Photo Source: morguefile.com
A surprising material has been found that displays the same industry standard thermal conductivity as diamond, with potentially far-reaching consequences for electronics manufacturers.
In a world where electronic devices are becoming smaller, faster and increasingly relied upon, the dissipation of the heat generated by these devices is an extremely important consideration for manufacturers. This requires an effective heat spreader within the system, with a high thermal conductivity (a material that absorbs heat readily). This allows heat to be transferred away from ‘hot spots’ within the given device, leading to better operating efficiencies. Applications include the semiconductor industry as well as optical and sensing applications.
In the production of these components today, diamond is usually the material of choice. Due to stiff chemical bonds between light carbon atoms, diamond has an incredibly high thermal conductivity, five times higher than the nearest metallic rival copper, at 2,000 watts per meter per Kelvin.
In the video below we see a simple yet powerful demonstration of the high thermal conductivity of synthetic diamond as it is used to cut through a block of ice like a knife through butter.
Cutting through Ice with Synthetic Diamond from Element Six
But are there any alternatives to diamond as a thermal conductor?
Step forward cubic boron arsenide. New research has measured the thermal conductivity of the material to be more than more than 2000 Watts per meter per Kelvin at room temperature, and even higher than diamond at higher temperatures.
What is especially remarkable is that the researchers did not expect to find anything particularly special about the thermal conductivity of boron arsenide. The thermal conductivity of the material had never been studied in depth, and it was predicted to be 10 times smaller than that of diamond.
However, unexpected vibrational properties led to a much higher than expected thermal conductivity, which may provoke a rethink of the guidelines commonly used to predict the thermal conductivity of materials.
Not only is this discovery potentially interesting from a commercial point of view, but it was made via a novel theoretical approach, which could lead to more discoveries in the future.
The research, which was recently published in the journal Physical Review Letters, was conducted by a team of theoretical physicists from Boston College and the Naval Research Laboratory.
Co-author David Broido, a professor of physics at Boston College, explains below the potential opportunities that the recent work presents:
This work gives important new insight into the physics of heat transport in materials, and it illustrates the power of modern computational techniques in making quantitative predictions for materials whose thermal conductivities have yet to be measured." "We are excited to see if our unexpected finding for boron arsenide can be verified by measurement. If so, it may open new opportunities for passive cooling applications using boron arsenide, and it would further demonstrate the important role that such theoretical work can play in providing useful guidance to identify new high thermal conductivity materials.