Spin-Lattice Relaxation and Spin-Phonon Coupling of ns¹ Metal Ions at the Surface

To use transition metal ions for spin-based applications, it is essential to understand fundamental contributions to electron spin relaxation in different ligand environments. For example, to serve as building blocks for a device, transition metal ion-based molecular qubits must be organized on surfaces and preserve long electron spin relaxation times, up to room temperature. Here we propose monovalent group 12 ions (Zn⁺ and Cd⁺) as potential electronic metal qubits with an ns¹ ground state. The relaxation properties of Zn⁺ and Cd⁺, stabilized at the interface of porous aluminosilicates, are investigated and benchmarked against vanadium (3d¹) and copper (3d⁹) ions. The spin-phonon coupling has been evaluated through DFT modeling and found to be negligible for the ns¹ states, explaining the long coherence time, up to 2 μs, at room temperature. These so far unexplored metal qubits may represent viable candidates for room temperature quantum operations and sensing.