Quantum simulations in nanoscale condensed matter physics

The latest version of the semiconductor technology roadmap reflects that the Si-based technology will reach absolute limits on its performance within the next decade. At the spatial scale of sub-0.1 μm, quantum effects start to become important, and it is difficult to achieve the acceptable reliability in devices. As a replacement for Si-based devices, a new concept of devices utilizing nanoscale materials, such as molecules, nanowires, nanotubes, and graphene, has been proposed and increases the demand of understanding and improving materials properties and device operation. First-principles electronic structure calculations, which only use the atomic numbers and masses as inputs, have become an important tool to explore the fundamental physics in condensed matter physics. This method enables us to design and predict new materials with improved properties and functionalities prior to experimental observations. This talk will cover the development of advanced density functional calculations and successful applications to a variety of nanoscale materials and systems such as Si/high-k and metal/high-k interfaces, oxide semiconductors, semiconductor nanowires, and graphene.