The research group led by Mathieu Luisier from the Integrated Systems Laboratory (IIS) at ETH Zurich started with a so-called quantum transport simulator software named OMEN, which runs its calculations based on what is known as density functional theory, allowing a realistic simulation of transistors in atomic resolution and at the quantum mechanical level. This simulation visualizes how electrical current flows through the nanotransistor and how the electrons interact with crystal vibrations, thus enabling researchers to precisely identify locations where heat is produced. In turn, OMEN also provides useful clues as to where there is room for improvement.
But so far, conventional programming methods and supercomputers only permitted the researchers to simulate heat dissipation in transistors consisting of around 1,000 atoms. Producing a realistic simulation of larger objects was impeded by a data communication bottleneck between the processors and memory requirements. Indeed most computer programs spend more time moving data between processors, main memory and external interfaces than performing actual computing operations. According to the scientists, OMEN also suffered from a pronounced bottleneck in communication, which curtailed performance.