HELICOMBX · Quantum spin Hall insulator with two dimensional crystals

Dissipationless electrical transport is a key paradigm to reduce energy consumption in our society. Recent advancements incondensed matter physics have revealed that there exist ballistic transport channels at the surface or the edge of topologicalinsulators. These states are preserved by time-reversal symmetry and robust against back scattering. Exploiting topologicalinsulators is therefore a major step for future nondissipative nanoelectronics.Nevertheless, such a topological phase of matter has been discovered in very few kinds of materials so far. Most of theexisting materials are difficult to fabricate, which limits scientific endeavor to explore their properties and also futureapplication. Recently, several theoretical studies have demonstrated that atomically thin graphene or other two dimensionalcrystals may become two dimensional topological insulators (quantum spin Hall insulators) by inducing large spin-orbitinteraction. These materials are rich of novel physics and attract growing attention in their own right. Moreover, they areeasy to prepare by mechanical exfoliation, which facilitates to apply them to real nanoelectronics devices.HELICOMBX is the first project which aims at establishing a basis for dissipationless electronics and spintronics withgraphene and transition metal dichalcogenides and unifying physics in topological phase, spintronics and two dimensionalcrystals. The project is divided into three parts. First we will induce large spin-orbit interaction in graphene by adatomsdeposition and heterostructures construction with transition metal dichalcogenides. Spin-orbit interaction of each system isthen measured by magnetotransport measurements. Second we will exploit these functionalized two dimensional crystals forspintronics devices. As the final part, quantized conductance will be measured as a signature of the edge states, and we willintegrate it into Josephson junctions to observe the Majorana fermions.