Resistance in nanoscale wires is increasingly the main bottleneck in the performance of semiconductor computing devices. With reducing dimensions, scattering of electrons at surfaces, interfaces and grain boundaries increases rapidly and causes a sharp increase of resistivity of conventional metals at the nano scale compared to bulk. We use first-principles calculations of ballistic electron transport and electron-phonon scattering to explore several complementary strategies to design materials for future nanoscale interconnects. We investigate strategies ranging from maximizing ballistic conductance of conventional metals, to the possibility of topological protection in surface-state conduction. We identify anisotropy and directionality of electronic states in metals as one of the most promising ways to achieve conductors that perform well at the nano scale. When designed correctly, such materials may mitigate surface scattering by getting the electrons to encounter the surface less frequently. From high-throughput electronic structure calculations of thousands of known intermetallics and metallic compounds, we propose promising directional conductors for narrow interconnects in future computing devices.
Ravishankar Sundararaman is an associate professor of Materials Science and Engineering at Rensselaer Polytechnic Institute. He received a PhD in Physics from Cornell University in 2013, and was a postdoctoral fellow in the Joint Center for Artificial Photosynthesis at Caltech till 2016. His research team pushes the limits of first-principles materials design using combined quantum-classical simulations for electrochemical, plasmonic and nano-electronic applications, and leads the development of the JDFTx open-source software for such calculations. He is the recipient of the AIME Robert Lansing Hardy Award in 2020 and the Rensselaer School of Engineering Research Excellence Award in 2020.