Acceptor-based qubit in silicon with tunable strain

Long coherence time and compatibility with semiconductor fabrication make spin qubits in silicon an attractive platform for quantum computing. In recent years, hole spin qubits are being developed as they have the advantages of weak coupling to nuclear spin noise and strong spin-orbit coupling (SOC), in constructing high-fidelity quantum gates. However, there are relatively few studies on the hole spin qubits in a single acceptor, which requires only low density of the metallic gates. In particular, the investigation of flexible tunability using controllable strain for fault-tolerant quantum gates of acceptor-based qubits is still lacking. Here, we study the tunability of electric dipole spin resonance (EDSR) of acceptor-based hole spin qubits with controllable strain. The flexible tunability of heavy hole-light hole splitting and spin-hole coupling (SHC) with the two kinds of strain can avoid a high electric field at the ``sweet spot'', and the operation performance of the acceptor qubits could be optimized. Longer relaxation time or stronger EDSR coupling at a low electric field can be obtained. Moreover, with asymmetric strain, two sweet spots are induced and may merge together, and form a second-order sweet spot. As a result, the quality factor $Q$ can reach ${10}^{4}$ for a single-qubit operation, with a high tolerance for the electric field variation. Furthermore, the two-qubit operation of acceptor qubits based on dipole-dipole interaction is discussed for high-fidelity two-qubit gates. The quality factors of single-qubit gates and two-qubit gates can be enhanced by 100 and 7 times respectively with tunable strain. The tunability of spin qubit properties in an acceptor via strain could provide promising routes for spin-based quantum computing.