Point contacts for quantum spin valleytronics (PCSV)

Since the discovery of the transistor in 1948, semiconductor electronics have changed our lives in unprecedented ways.

The enormous miniaturization of transistors, which has triggered an exponential increase of the world’s computational power, is reaching a fundamental limit.

In this context, the achievement of complex operations by alternative approaches is crucial for the future of computation.

A recently developed alternative relies on the quantum entanglement between the ultimately small quantum dots (QD) and has already proved to be faster than conventional computations for certain operations.

PCSV explores van der Waals heterostructures made of bilayer graphene (BLG), tungsten diselenide (WSe2), and hexagonal boron nitride (hBN) to achieve a novel QD platform where single spins are the information carriers and its coherence time can be controlled electrically.

For this purpose, PCSV studies electrostatically defined quantum point contacts (QPCs) and QDs in a BLG/WSe2-based novel device platform where the WSe2 layer imprints its strong spin-orbit coupling (SOC) on BLG.

Using electrostatic gates, I will define QPCs and QDs where the direction of the perpendicular electric field determines which layer of the BLG dominates the charge transport.

Since only one of the layers is proximitized, this modulation will lead to the realization of QPCs and QDs with highly tunable SOC and spin coherence times.

Furthermore, PCSV will explore the spin filtering possibilities of the QPC device geometry using spin-polarized electrodes.

PCSV will become a feasibility study to determine whether BLG/WSe2 heterostructures can compete with state of the art spin QDs for quantum computation and as a spin filter for conventional spintronics.