Description
Topological edge states are potential quantum information carriers. In this talk, I will discuss our effort in realizing the quantum valley Hall effect and the properties of its edge state, the kink states. Using van der Waals stacking and precision lithography, we create valley-momentum locked kink states in bilayer graphene and demonstrate its precise resistance quantization, a hallmark of ballistic edge state transport. The quantization is robust to temperatures of tens of Kelvin, which bolds well for potential applications. The all-electrical construction of the kink states gives us the ability to realize a variety of electron quantum optics operations, now in an edge state platform. I will show the workings of a topological switch, a reconfigurable ballistic waveguide, a topological valley valve, and a continuously tunable electron beam splitter. Time permitting I will also discuss the evolution of the kink states in a magnetic field, where its four-fold degeneracy can be sequentially broken to result in a single pair of spin-momentum locked edge modes. Our ongoing experiments explore its potential as on-chip quantum interconnects.
