Quantum short channel transistor of twisted bilayer graphene in vacuum diaphragm

We investigated a quantum short-channel transistor based on coherent tunneling in twisted bilayer graphene (TBG). The opposite valley chiralities generate Berry geometric curvature that mediates inter-valley coherent electron tunneling. This is analogous to the interference of electrons in a double-slit experiment under a vector potential of the Aharonov–Bohm effect. The effective low-energy Hamiltonian of TBG exhibits a pseudospin structure that is formally equivalent to a single-particle qubit Hamiltonian, enabling direct mapping between valley coherence and quantum bit operations. We designed an hBN/TBG encapsulated vacuum-bridged diaphragm for room-temperature operation. Under appropriate geometric and dielectric conditions, the device partially preserves robust coherence, demonstrating a pathway toward scalable, solid-state quantum information devices.