Full Configuration Interaction Simulations of Electron and Hole p-Orbital Qubits in Silicon and Germanium

We investigate the properties of semiconductor p-orbital (pO) charge qubits, which encode information in the orbital states of electrons or holes confined in gate-defined quantum dots. Compared to conventional charge qubits, pO qubits offer reduced sensitivity to charge noise due to their vanishing dipole moment and ability to operate within a single dot. Using full configuration interaction (FCI) calculations, we study both five-electron systems in silicon and three-hole systems in germanium, each exhibiting p-like orbital character in their highest occupied states. We analyze their charge densities to extract dipole and quadrupole moments and assess coupling to electric fields. By combining these results with confining potentials derived from Schrödinger–Poisson device simulations, we examine how realistic gate tuning influences orbital energies and qubit controllability. These results demonstrate the potential of both silicon and germanium as viable host materials for p-orbital qubits.