Interface effects on acceptor qubits in silicon and germanium

TL;DR

This paper investigates how interfaces in silicon and germanium affect acceptor qubits, focusing on energy level modifications, symmetry breaking, and implications for quantum computing applications.

Contribution

It provides a detailed analysis of interface-induced effects on acceptor energy spectra using effective mass theory, highlighting symmetry breaking and optical transition impacts.

Findings

Interface causes splitting of ground state into two Kramers doublets

Inversion symmetry breaking leads to parity mixing

Impacts on optical transitions for acceptor qubits

Abstract

Dopant-based quantum computing implementations often require the dopants to be situated close to an interface to facilitate qubit manipulation with local gates. Interfaces not only modify the energies of the bound states but also affect their symmetry. Making use of the successful effective mass theory we study the energy spectra of acceptors in Si or Ge taking into account the quantum confinement, the dielectric mismatch and the central cell effects. The presence of an interface puts constraints to the allowed symmetries and lead to the splitting of the ground state in two Kramers doublets [J. Mol et al, App. Phys. Lett. 106, 203110 (2015)]. Inversion symmetry breaking also implies parity mixing which affects the allowed optical transitions. Consequences for acceptor qubits are discussed.