Heat is something of a nuisance for electrical engineers. It reduces the reliability of electronic devices and even causes them to fail completely. That’s why computer components are liberally smeared with thermal paste and connected to heat pipes, fans, and even water cooling systems.
The goal is to channel the heat away from sensitive components so that it can dissipate into the environment. But as devices get smaller, the challenge becomes more acute—and modern transistors, for example, are measured in nanometers.
The most cost-efficient conductors are metals such as copper, but heat travels through them equally well in all directions. That means heat can spread to any other component that is also in thermal contact with the metal.
A more effective conductor would channel heat in one direction but not in the perpendicular one. In this case, heat would travel along such a material but not across it.
This kind of asymmetric conductor would make the life of thermal engineers significantly easier. But creating them is hard.