Impact of the valley orbit coupling on exchange gate for spin qubits in silicon

Abstract The mixing of conduction band valleys plays a critical role in determining electronic spectrum and dynamics silicon nanostructure. Here, we investigate theoretically how valley–orbit coupling affects the exchange interaction double quantum dot. We find that splitting can be strongly suppressed at finite valley phase differences between dots because valley-phase-dependent dressing ground states Coulomb integrals, small render Hamiltonian incomplete describing low-energy due to nearby excited states. higher orbital are also vital calculating splitting, which is crucial for applications such as gates spin qubits.