Control of Giant Orbital Magnetic Moment and Valley Splitting in Bernal Stacked Trilayer Graphene*

The valley degree of freedom in two-dimensional (2D) materials is promising for applications in quantum technologies such as information storage, processing, and reading. In general, however, the valley degree of freedom in 2D materials is difficult to control because valleys are often degenerate or possess different energies that are indistinguishable experimentally. Therefore, an important step toward the realization of valley-based quantum information technology is the capability and control of valley splitting. In this regard, Bernal stacked trilayer graphene (ABA-TLG) is promising because it has two valleys that can be configured to host giant opposite non-zero orbital magnetic moments. In this talk, I will show our recent scanning tunneling spectroscopy (STS) study of ABA-TLG with magnetic field and back gate modulation. By applying an out-of-plane magnetic field we couple to the orbital magnetic moments in ABA-TLG and realize giant valley splitting. Subsequently, by modulating the back gate voltage in our devices we can tune the valley splitting by a factor of 2 at a constant magnetic field.