Ab Initio Design of Molecular Qubits with Electric Field Control

Area of Science:

• Quantum Information Science
• Molecular Quantum Computing
• Computational Chemistry

Background:

• Superconducting qubits, while competitive, present scalability challenges due to large footprints and complex interconnections.
• Molecular qubits offer atomic scale and tuneable properties, presenting a promising alternative for quantum computing.
• Current molecular spin manipulation is limited by techniques like electron paramagnetic resonance (EPR) spectroscopy, which address macroscopic ensembles.

Purpose of the Study:

• To explore the theory of spin-electric coupling in lanthanide molecules.
• To outline ab initio methods for designing molecules with enhanced electric field responses.
• To demonstrate precise, selective, and coherent manipulation of molecular spins using electric fields.

Main Methods:

• Investigated spin-electric coupling using ab initio computational methods.
• Analyzed structural distortions induced by electric fields and their impact on the crystal field Hamiltonian.
• Employed perturbation theory to understand magnetic and electric field orientation dependence.
• Utilized pseudo-symmetry point groups to decompose molecular distortions and analyze symmetry's role.
• Developed an analytical electric field model for efficient computation.

Main Results:

• Demonstrated that structural distortions under electric fields generate coupling elements in the crystal field Hamiltonian.
• Showcased the significant impact of molecular geometry on spin-electric coupling phenomena.
• Rationalized the orientation dependence of spin-electric coupling through perturbation theory.
• Identified the role of symmetry in spin-electric coupling via molecular distortion decomposition.
• Developed a computationally efficient analytical model for investigating experimentally relevant electric field strengths.

Conclusions:

• Spin-electric coupling in lanthanide molecules provides a pathway for coherent spin manipulation.
• Ab initio methods and molecular design can enhance electric field responses for quantum applications.
• The developed analytical model facilitates the exploration of molecular spin control at experimentally accessible electric field magnitudes.